[CHEMISTRY]: Gases: Chemical Properties of Gases, [CHEMISTRY]: Chapter 2: Gases-- Kinetic Molecular Theory (KMT)

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What is the chemical equation for the oxidation of aluminum?

1. Al + O₂ → Al₂O₃ Crossover rule: Al⁺³ and O⁻² ... Al₂O₃ 4 Al + 3 O₂ → 2 Al₂O₃

What are the main points to kinetic molecular theory (KMT)?

1. All matter consists of particles: either atoms or molecules 2. All particles are in constant motion 3. Their collisions are perfectly elastic; meaning they bounce back 4. For ideal gases only: the forces between particles are negligible, meaning small enough to be ignored. 5. The kinetic energy of a gaseous particle is directly proportional to the temperature of a gas

What is room temperature in kelvin?

298 k...

Quiz Q: Simple algebra, be careful...

49.70 mL/min / v₂ = 1.27 49.70 mL/min = 1.27v₂ 49.70 mL/min/1.27 = v₂ 39.13 = = v₂

What is the absolute temperature of 5?

5 k, kelvin

How many molecules are contained in 65 L? (the number of moles solve is 2.7 mol)

6.02 x 10²³/mol = x / 2.7 mol x = 1.63 x 10²⁴ molecules

Daily Uses of Gases: How does a neon sign work?

A neon light consists of a glass tube filled with a small amount (low pressure) of neon gas. Neon is used because it is one of the noble gases. One characteristic of these elements is that each atom has a filled electron shell, so the atoms don't react with other atoms and it takes a lot of energy to remove an electron. There is an electrode at either end of the tube. A neon light actually works using either AC (alternating current) or DC (direct current), but if DC current is used, the glow is only seen around one electrode. AC current is used for most neon lights you see. When an electric voltage is applied to the terminals (about 15,000 volts), enough energy is supplied to remove an outer electron from the neon atoms. If there is not enough voltage, there will not be enough kinetic energy for the electrons to escape their atoms and nothing will happen. The positively charged neon atoms (cations) are attracted to the negative terminal, while the free electrons are attracted to the positive terminal. These charged particles, called plasma, complete the electric circuit of the lamp. http://chemistry.about.com/od/colorchemistry/fl/How-Neon-Lights-Work.htm

Daily Uses of Gases: What are some daily uses of gas?

A neon sign Airbag Balloons Anesthesiologist

What's the difference between atoms and molecules?

An atom is just that, a single atom, made from protons, neutrons and electrons. A molecule is a group of atoms bonded together via ionic, metallic or covalent bonding.

In the combustion of a hydrocarbon, what are the products?

Carbon dioxide (CO₂) and water vapor (H₂O).

What is a common reaction that involves gases?

Combustion

As temperature increases, volume increases. How does this explain SATP?

Compared to STP, where the volume is equal to 22.4 L/mol, at SATP, the temperature increases. Therefore since temperature and volume are proportional, the volume will increase since in SATP, the temperature is increased to 298 k (compared to 273 k).

Test Q: Neon gas is pumped inside glass tubing to make a "neon sign" for a video arcade. The glass tubing has a volume of 2.40x10² mL and the gas exerts a pressure of 3.60x10² kPa. The same mass of neon gas, at the same temperature, is used to make another sign with a volume of 6.30 x 10² mL. How much pressure would be exerted by the neon gas?

Compile your data: V1 = 2.40 x 10² mL P1 = 3.60 x 10² kPa Molar mass is constant, and so is temperature. V2 = 6.30 x 10² mL Use Boyle's Law: P₁V₁ = P₂V₂ 3.60 x 10² kPa x 2.40 x 10² mL = P2 x 6.30 x 10² mL P2 = 137.14 kPa

What does diffusion and effusion have anything to do with Graham's Law?

Different gases diffuse at different rates, depending on their molar masses (see Chapter 7 for details on molar masses: I'm guessing in the chemistry workbook for dummies). The rates at which two gases diffuse can be compared using Graham's Law. Graham's Law also applies to effusion, the process in which gas molecules flow through a small hole in a container. Whether gases diffuse or effuse, they do so at a rate inversely proportional to the square root of their molar mass. In other words, more massive gas molecules diffuse and effuse more slowly than less massive gas molecules.

In a mixture of gases, 35% of it is composed of methane gas. If the partial pressure of methane is 55 kPa, what is the total pressure?

Do proportions: 35% / 100% = 55 kPa / x x = 157.14 kPa...

If not everything in the equation were in (g), then how would you solve for the volume if it were in SATP/STP?

Do the molar ratio (like in stoichiometry), then do the molar VOLUME ratio. Example: 2 mol C₂H₅OH / 4 mol CO₂ = 0.112 mol C₂H₅OH / x mol CO₂ x = 0.224 mol CO₂ 22.4 L / 1 mol = x / 0.224 mol CO₂ x = 5.0176 L of CO₂

Trick for molar formulas.

Do the triangle thing, it becomes: "mothers not Mothers"...

Which one is more reactive? Group 6 or group 7?

Elements from group 6 are more reactive because they need 2 electrons to complete their outer shell. Elements from group 7 are less reactive because they only need one electron.

Why can you smell perfume?

Because of effusion, if the door were closed and there was a slit at the bottom, let's say. It's also diffusion and because gases can translate. Gases are also very far apart so they can mix with other gases (diffusion). Gases are very small too, which allows them to effuse.

Why does an increase in temperature also increase pressure?

By heating a gas, you add kinetic energy to the particles; as a result, the particles collide with greater force upon other objects, so those objects experience greater pressure.

How would you determine whether a gas is stable or not?

By its bond. For example, a gas is more stable if it has a triple bond compared to a single or even double bond. That is why nitrogen gas is used to inflate air bags; it's because it can hold together strongly due to its triple bond, so it won't react as easily.

What are other less common oxidizers?

Fluorine gas (F₂), chlorine gas (Cl₂) and hydrogen peroxide (H₂O₂). Though there are more, these are just a few examples.

Gases are used in many technological applications. How?

For example, such as the manufacturing of energy-efficient windows.

What are some greenhouse gases?

In order, the most abundant greenhouse gases in Earth's atmosphere are: Water vapor (H 2O) Carbon dioxide (CO2) Methane (CH 4) Nitrous oxide (N 2O) Ozone (O 3) Chlorofluorocarbons (CFCs)

What does "ambient temperature" mean?

It just means 298 K AND 101.3 kPa!... (since temperature does have an effect on pressure)

Why is the use of hydrogen as a fuel limited?

It requires a lot of energy to produce.

Is kelvin a capital letter or lower-case letter?

It's a capital letter: "K"...

Which of the following occurs when a gas is heated? Its molecules gain more kinetic energy. It condenses to a liquid. It causes all of the bonds to get broken. It turns into plasma.

Its molecules gain more kinetic energy. Plasma by the way is The state of matter that does not have a definite shape or volume and is made up of electrically neutral particles...

A teacher combines hydrogen gas at 125 kPa and neon gas at 235 kPa and carbon dioxide at 325 kPa. What is the total pressure of the mixture?

Just add all your values: 125 kPa + 235 kPa + 325 kPa = 685 kPa...

Inversely proportional graph

Know how the graph looks! And know where P and V goes on the axes. The dependent variable is normally on the x-axis, while the independent variable is on the y-axis. Usually the x-axis is the independent variable and the y-axis is the dependent variable. That means that pressure is a function of x, since P is on the y-axis and V is on the x-axis. They are related to each other, it's not that one depends on the other.

How much faster does hydrogen gas effuse than neon gas?

Since we're talking about effusion, we will use Graham's Law since effusion ties into Graham's Law. It is as follows: v₁/v₂ = √M₂/M₁ Let's start with what we know, that being the molar masses: H₂ = 1 x 2 = 2 g/mol Ne (there is no "Ne₂"): 20 g/mol We also know that Graham's Law deals with an inversely proportional relationship, so apply the second part of the formula; DO NOT FORGET TO SQUARE ROOT... AND MAKE SURE THE GREATER VALUE GOES ON TOP OF THE SMALLER VALUE... √(20/2) = 3.2 So, dihydrogen effuses 3.2 times faster than neon.

All matter is composed of particles (ions, atoms or molecules) that are infinitely small with more or less space between them depending on their phase. How does the phase change with the distance between the particles?

The closer the particles are to one another, the more solid it is.

Lab demo: Describe the contents of the can after the heating process.

The inside of the can had warm air (not just H₂O, other gases as well), water vapor and hot water.

Which ion or element goes first when doing the crossover subscript rule?

The metal (i.e. the positive ion)

Workbook explanation of Boyle's Law

The relationship makes good sense in light of kinetic molecular theory. At a given temperature and number of particles, more collisions will occur at smaller volumes. These increased collisions produce greater pressure. And vice versa.

Plasma

The state of matter that does not have a definite shape or volume and is made up of electrically neutral particles

How does electrolysis work?

Think of the two electrodes with a voltage difference between them. That means that there's an electric field in the water between them. So any H+ ions get pulled one way, OH- ions get pulled the other. Look at the electrode where the H+ ions gather. It has a negative voltage- too many electrons. Electrons can leave the electrode and join up with a pair of H+ ions to make the H2 molecule. The reaction over where the OH-'s gather is a little more complicated, but by donating electrons to the positive electrode they can form water molecules and O2 molecules. This process doesn't use up the ions, because more H2O water molecules keep falling apart to make up more H+ + OH- ions. When there's no voltage on, that's also happening but it's balance by ions recombining to make H2O. The process gets a bit more complicated if there are other ions around, but this simple example may get you started.

Describe the graph for the general gas law. What can we deduce from this graph?

Title: PV vs nT x-axis: nT (molK) (n x T) y-axis: PV (kPaL) Line: straight and goes through (0,0) Since PV vs nT provides us with a direct variation function, then the slope, PV/nT is a constant, k: PV/nT = k (it's like doing y2-y1/x2-x1 = a) Ask Dad if it's not an ideal gas, if "k" represents the temperature. For the PV vs nT graph, the points are the products. Keep this in mind when plugging into general gas law formula... Also, the slope is R = 8.31 kPaL/molK if molK units are used for nT (x-axis) and kPaL units are used for PV (y-axis)... Also, the slope is R = 0.082 atmL/molK is the units that are being used for nT are molK and the units that are being used for PV are kPaL...

Trick to knowing capital/lower-case letter V, v?

Look at the second letter of the word...: VElocity, therefore lower-case (e occurs first before o in the alphabet), and VOlume, therefore capital V.

Particles of matter are always moving. True or false?

True

What are the different formulas for moles?

MEMORIZE... 1. n = m/M 2. n = PV/RT 3. n = C x V

To what temperature must a gas in a rigid container be heated in order to double the pressure it exerts at 20°C?

Make up your own numbers for this. So for example, we have: P₁ = 9 kPa P₂ will be doubled, so 9 x 2 = 18 kPa T1 = 20 degrees Celsius + 273 K = 293 K, it is the initial temperature because they want to know the final temperature after you heat it up T2 = ? Use Gay-Lussac's Law to solve, should get 586 K

True or false: All particles are in constant motion.

True

What is the most common oxidizer?

Oxygen gas (O₂)

Textbook pg. 51 #7. Give two examples of gas in the living world.

O₂: involved in respiration AND it is ozone. Ozone protects us from UV rays. CO₂: also involved in respiration and is a greenhouse gas

True or false. Gas particles also move in a random fashion.

True.

Quiz Q: True or false? At the same temperature and pressure, two samples of gases with different molar masses will have different average molecular velocities.

True. If we look at Graham's Law: v₁/v₂ = √M₂/M₁, we can see that the velocity and molar mass are inversely proportional, meaning that heavier molecules will move slower than lighter molecules, thus affecting the velocity: that is what "different molar masses will have different average molecular velocities"..., provided that temperature and pressure are constant (which as you can see are excluded from the formula of Graham's Law) (Ask Dad: In the formula, usually the numerator is directly proportional to the denominator. How come this isn't the case here?). Temperature has an effect on velocity... the speed is dependent on mass: heavier molecules move slower... Molar mass AKA mass...

Electrolysis can be used to separate water into its two gaseous components: hydrogen and oxygen. True or false?

True: Electrolysis of water, or running an electric current through it, uses a lot of energy. However, it does allow clean cycle hydrogen gas (and oxygen gas) to be produced...

Avogadro's Number... MUST KNOW...

NA = 6.02 x 10²³ particles/molecules/ions per mol (the "A" is a subscript...) To find out the number of molecules, use a ratio.

Since V ∝ n, that means that...

V/n = k. So if you take two points and you get the slope, that's y/x, so V/n = k, the slope, which is always the same value (and it is temperature in Kelvin).

If: A (V1, P1) --> V1 x P1 = k B (V2, P2) --> V2 x P2 = k EXACT SAME "k" VALUE! Then what is Boyle's Law?

V1 x P1 = V2 x P2 OR you could write it as: P₁V₁ = P₂V₂. It's just in alphabetical order this way. Since the k value will be the same, you could just equate the two together (P1, V1, P2, V2)

What does upper-case V represent? Lower-case v? Lower-case t? Upper-case T?

Volume, V. Velocity, v. Time, t (not in one of the simple gas laws). Temperature, T (in one of the simple gas laws)

Jacques Charles's ghost attempts to inflate his sagging celestial hot air balloon with short bursts from a burner. The initial volume of the balloon is 300L (ghosts don't require large balloons). Trying to impress the passing spirit of a recently departed séductrice, Jacques lets fly a long burst from the burner. The long burn increases the temperature of the air within in the balloon from 40.0°C to 50.0°C. How much does the balloon inflate?

V₁ = 300 L T₁ = 40 + 273 = 313 k T₂ = 50 + 273 = 323 k Charles' Law: V₁/T₁ = V₂/T₂ 300 L / 313 k = V₂ / 323 k V₂ = 309.58 L

What is the formula for Charles' Law? What are the constants?

V₁/T₁ = V₂/T₂. The constants are pressure and # of moles.

What is the formula for Avogadro's Law? What are the units?

V₁/n₁=V₂/n₂ n is in moles, mol. V can be anything, but it has to be consistent. So it can be in L, ml, and cm³.

When temperature is kept constant (notice how T, temperature, is excluded from the Boyle's Law formula), the pressure and volume of a gas are inversely proportional to one another. What equation represents this? Explain.

P ∝ 1 / V This is because the V is on the x-axis and the P is on the y-axis. Basically, P = 1/V.

What is the formula for Dalton's Law? What do the components represent?

P(total) = P(a) + P(b) + P(c)... PT = total pressure of the mixture PA, PB, PC: partial pressure for each individual gas in the mixture. The letters following P must be subscripts and are usually replaced by elements/compounds...

Explain the following phenomenon using the particle model of matter: Water vapor can mix with air to make it humid.

Particles are always moving and particles of matter attract or repel each other, and the force that attracts or repels them from each other varies because in this situation there's a change of phase

What size are particles? Explain.

Particles are infinitely small; not measurable by any instrument, but they're still present.

Explain the following phenomenon using the particle model of matter: The smell of skunk spray seeps into a house even when the windows are closed.

Particles of matter are always moving and are infinitely small because they can move through small spaces.

Textbook pg. 51 #6. a. What are the products resulting from the complete combustion of hydrocarbons?

Water vapor (H₂O) and carbon dioxide (CO₂)

Avogadro's Law: What are the constants? What do "constants" mean?

Pressure and temperature, meaning that they're the same value.

What relationship does Boyle's Law deal with?

Pressure and volume

Ask Dad: Is n directly proportional to T? (General gas law)

No. Temperature does not affect number of moles.

Are the forces negligible for water? Explain.

No; for water, the forces between particles are NOT negligible. Water doesn't play by the rules and in fact there are many unique things about water.

What is the name of group 8 in the PT?

Noble/Inert gases

Textbook pg. 51 #16. How do the electron configurations of noble gases and halogens describe their particular chemical reactivity?

Noble: unreactive due to full outer shell Halogens: very reactive because need electrons to fill up their last shell

What are the units for Boyle's Law?

Recall that Boyle's Law is: P₁V₁ = P₂V₂. The units don't matter. Pressure must be in either kPa or atm. Volume can be in any unit. Just be consistent with the units.

At a given temperature, the rate of diffusion of oxygen gas is 0.82 m/s. Find the rate of diffusion of neon gas at this temperature.

Recall that Graham's Law states that when temperature and pressure are constant (notice how these variables are not in the formula), the rate at which a gas moves (DIFFUSION or effusion) is inversely proportional to the square root of the molar masses. 1. Use the formula: v₁/v₂ = √M₂/M₁ 2. Find the molar masses: Oxygen gas: 32 g/mol Neon: 20 g/mol 3. Plug in your values to the formula. Doesn't matter whether you say Neon is 1 or 2 (same thing for the velocity's)... Just make sure it corresponds to V's subscript. Same thing for oxygen gas. ALWAYS PUT DOWN YOUR UNITS. v₁/v₂ = √M₂/M₁ 0.082 m/s/v₂ = √20g/mol/32g/mol DIVIDE FIRST, THEN SQUARE ROOT: V₂ = 0.10 m/s for neon Neon is lighter, so it's moving faster than oxygen gas. If you look at both velocity values, it makes sense.

Charles' Law: When temperature is in Celsius, what is the x-intercept?

Recall that for this law, the temperature (in kelvin) goes on x-axis. The x-intercept will be -273 because you must add 273 to Celsius to convert any temperature to kelvin.

What is the molar volume at STP? At SATP? MUST MEMORIZE...

STP: 22.4 L/mol SATP: 24.5 L/mol

At STP, a gas occupies 0.5 L in a rigid ball. What pressure will the nanometer display if the ball is submerged in a container filled with water at 20°C?

STP: P₁ = 101.3 kPa, T₁ = 273 k T₂ = 20°C + 273 k = 293 k P₂ = ? Use Gay-Lussac's Law to solve

Txtbk p. 99 #47: Using the kinetic theory of gases, explain why the values of molar volume of a gas are different at STP and SATP.

STP: T = 273 K SATP: T = 298 K V is proportional to T. So as T increases, V (molar volume) increases as well... That's why it's 22.4 L → 24.5 L...

Boyle's Law: What is the general equation for the graph representing P vs. V? Explain.

Since xy = a (OR y = a/x, simply cross multiply), and since P is on the y-axis and V is on the x-axis, you have P x V = k. This means that for every point on the graph, when you multiply P and V, you'll always get the same answer of the k value. Remember that "k" means temperature that is measured in kelvin. And remember that in Boyle's Law, the temperature is constant-- that's why it's always the same answer of the k value. For example, you have the following points: A (V1, P1) --> V1 x P1 = k B (V2, P2) --> V2 x P2 = k EXACT SAME "k" VALUE!

The atomic structure of a gas is largely responsible for its reactivity. Explain.

Smaller atoms have an easier way of reacting as opposed to bigger atoms.

What does SATP stand for?

Standard Ambient Temperature and Pressure

What does STP stand for?

Standard Temperature Pressure

What does STP stand for? Must know this...

Standard Temperature and Pressure

What kind of relationship in Boyle's Law? What must be kept constant?

When temperature is kept constant (notice how T, temperature, is excluded from the Boyle's Law formula), the pressure and volume of a gas are inversely proportional to one another.

Lab demo: What happened to the soda can at the end of the demonstration? Why did it implode?

When the soda can was placed in the water bath, no air is able to go in or out of the can. As the can experiences a drop in temperature because of the water which is colder than the can that has just been heated up, the pressure inside the can also goes down as a result, therefore the pressure of the water in the water bath is great enough to crush the can. Pressure and temperature are directly proportional (Gay-Lussac's Law). Pressure is defined as the amount of force exerted on a given area. The pressure DIFFERENCE (which is going to be very big because of hot vs. cold) between the inside of the can and the outside of the can is what caused it to implode. Also, when the can is placed in the water bath, the steam inside the can condenses and takes less room, which makes the pressure in the can drop. There's less steam/gas inside the can, so there's less pressure inside the can because the steam has been condensed, but the volume of the can is still the same.

Describe the relationship between volume and temperature in Charles' Law.

When the temperature of a gas is increased, the energy of the particles will increase. This increase in energy results in an increase in the particle's speed, resulting in more collisions with greater force (also resulting in an increase in pressure).(The gas particles will move farther out and push wall even more and occupies more space). When the molecules move at a greater speed, they move further from one another and take up more space; thus results in an increase in volume because the particles will want to take up more space. Volume affects how close they are to one another. The reverse is true.

When would you be asked to solve for R, the constant? (ideal gas law)

When you are asked whether it's an ideal gas.... If the R = 0.082 atmL/molK or 8.31kPaL/molK (careful of units)... then it is an ideal gas...

Test Q: At 20°C, a syringe contains a given volume of oxygen gas, O₂, at a pressure of 100 kPa. When the temperature is raised to 40°C while the pressure is kept constant, the volume of gas stabilizes at 20 mL. What is the initial volume of gas in the syringe?

T1 = 20 + 273 = 293 k P1 = 100 kPa, which stays constant, so this means that P2 will ALSO be 100kpa. Since pressure is a constant, the formula used will NOT include pressure. T2 = 40 + 273 = 313 k V2 = 20 mL Use Charles' Law: V₁/T₁ = V₂/T₂ V₁/293 k = 20 mL/313 k V1 = 18.72 mL

If the gas being studied is an ideal gas, then the constant is equal to what?

TWO CONSTANTS: R = 8.31 kPaL/molK = 0.082 atmL/molK

What are the constants in Gay-Lussac's law?

Since Gay-Lussac's law is the relationship between temperature and pressure, the constants will be the volume and the number of moles. So whatever is excluded from the formula.

Dalton's Law: P(total) = P(a) + P(b) + P(c)... what happens to the P(total) if the number of moles is halved?

Since P is directly proportional to the number of moles, then the P will be halved, too (ask Dad if correct).

How does the disorder of a gas compare to that of a liquid or solid? Explain.

Since gas particles move freely, the gas phase is extremely disorderly compared to the liquid phase (which is less so) and the solid phase (where there is very little disorder).

Test Q: What happens to the pressure of a gas when its volume is doubled and the temperature is changed from 100°C to 50°C?

Since pressure and volume are inversely proportional to one another, if the volume is doubled, the pressure will be halved (or, in other words, decreased by a factor of 1/2 or ask Dad if we can say decreased by a factor of 0.5 or decreased by 0.5 times?). Temperature: it is directly proportional to pressure and volume. So when the temperature decreases, so will the pressure and volume (by the same factor). Ask Dad to explain further.

What is the change in the pressure if the temperature in Kelvin is tripled? Assume that the number of moles and volume are constant.

Since temperature and pressure are directly proportional, then the pressure will triple as well. It is 3 times its original value.

Mystery Gas A effuses 4.0 times faster than oxygen. What is it the likely identity of the Mystery Gas?

Since we're talking about effusion, we will use Graham's Law since effusion ties into Graham's Law. It is as follows: v₁/v₂ = √M₂/M₁ Let's start with what we know, that being the molar mass of oxygen gas: it is a gas because gases can effuse (and diffuse). It is a physical property of a gas. Liquids can also diffuse and effuse. 16 g/mol Like the previous example, we'll only apply the second part of the formula with the factor change... A lightweight gas will move faster, that's why you divide 32 by 16. If it said that it moved 4 times slower, then you would do 32 x 16 = 512 g/mol, because a heavier molecule will effuse slower. 4 = √32/M₁ Square the four to get rid of the square root 16 = 32/ M1 M1 = 2 g/mol, which is hydrogen gas... It is always a gas because we're dealing with effusion/diffusion. So for chapter 2, everything is in gas so long as it's part of the mneumonic: "I Have No Bright Or Clever Friends" : hydrogen, nitrogen, fluorine, oxygen, chlorine, iodine, and bromine

What does "saturate its electron" mean?

electron configuration

What does an oxidation reaction require?

an oxidizer

Since gases translate, they can collide with other particles or the walls of their container. These collions do what?

apply force

How is pressure defined?

as the amount of force exerted on a given area.

At a given temperature, the molecules of ALL gases have the same what?

average kinetic energy. So it doesn't matter which gas/element/compound it is, it will always be the same

Why is hydrogen gas ideal for fires?

because it is flammable

Why is nitrogen gas, N₂, very stable?

because of its triple bond (do the Lewis Dot diagram and you'll see)

Why does the mean/average kinetic energy of particles increases as the temperature of the gas rises?

because the higher the temperature of a gas, the faster its particles move.

Why are halogen gases very reactive?

because they only need one valence electron to complete their outer shell

Textbook pg. 51 #6. b. What is the difference between a yellow flame and a blue flame during the combustion of methane?

blue flame: contains carbon dioxide and water, which are the products of the combustion reaction. This is a complete combustion. The reactants have been completely burned. yellow flame: when the reactants are not completely burned, the residue colors the flame yellow. This is an incomplete combustion.

How can we use nitrogen gas to our advantage?

by adding it to potato chips bags because it's not as reactive

What's another way we can produce hydrogen gas?

by passing it through electrolysis, which involves passing a current through water

What is a gas' volume determined?

by their container, not by the size of individual molecules

What do hydrocarbons contain?

carbon and hydrogen

What do cars emit?

carbon dioxide AND carbon monoxide.

What is kinetic energy?

energy of motion

What does the property of expansion allow a gas to do? Explain.

fill up any space since they can move randomly in any direction

Gases are compressible. What does this allow?

for the expansion and dispersion (scattering) through diffusion and effusion

How can we use combustion to our advantage?

for warmth, fuel

How do gas molecules move?

from one point to another

What three things must be present for combustion to happen?

fuel, oxidizer and the source of ignition

Units for density

g/mL or g/cm³ or g/ml or kg/m3 1 mL = 1 cm³...

Water vapor (H₂O) is water in what state/phase?

gaseous

For ideal gases only: the forces between particles are negligible, meaning small enough to be ignored. This is virtually (practically) the case for which gases?

gases like helium, nitrogen and oxygen, but is not as valid for gases like water vapor, whose particles are attracted to one another.

Which of the following phases of matter have translational motion?

gases mainly (even though liquids have it too)

What is translation motion?

goes up and down

How do fire extinguishers fires?

has CO₂, which extinguishes fires

What makes gas particles move faster? Explain.

heat; absorbed energy converted into kinetic energy

The three modes for vibrational motion...

https://www.youtube.com/watch?v=xITzGUjongU

What are some combustible gases?

hydrogen gas (H₂) and hydrocarbons such as methane (CH₄) and propane (C₃H₈).

V ∝ n only works if what?

if all the components in the chemical equation are gases, (g) (THEN you can use molar volume ratio...) Ask Dad why.

What are manometers?

instruments used to measure pressure

Biogas

involves heating up organic materials, which releases greenhouse gases such as methane, carbon dioxide and other gases known as biogas. The waste is then transformed into fertilizer.

What does "biological" mean?

involves life and living organisms

What does the chemical reactivity of a gas mean?

is its tendency to undergo a chemical change under the effect of various factors such as heat, light, and contact with other substances.

What is kPaL?

it is a multiple of P x V

What is diffusion?

it is when gases mix and blend in with other gases in a container; diffusion is a slow process (at least if we don't aid it into diffusion, for example, heating it), and it can take a while for the gas to blend in uniformly.

The kinetic energy of a gaseous particle doubles. What will happen to the temperature of the gas?

it will double as well because kinetic energy and temperature are directly proportional to each other

To make use of the general gas law, temperature value must be in what?

kelvin, k

Continue this Quizlet with sister's tests: the one with the ideal gas law and the ones on the quiz on Boyle's Law, Charles' Law, and Combined Gas Law (the ones I didn't put, the ones with the combined gas law, do ctrl+f on Quizlet to find out the ones I didn't put.

kkk

As learned in kinetic molecular theory, the distance between gas particles is very large or small?

large, since the particles can move more freely

At 25°C, a gas has a pressure of 700 mm Hg. If the container is heated to 50°C, what is the final pressure exerted by the gas?

mm Hg is just another unit for pressure... T₁ = 25°C + 273 k = 298 k P₁ = 700 mm Hg T₂ = 50°C + 273 k = 323 k P₂ = ? Use Gay-Lussac's Law to solve

We measure the quantity of gas particles in what?

moles, n.

Gases can be in compound. What does that mean? Give examples.

more than one TYPE of element/atom: H₂O, CO₂

What is the formula for number of moles?

n = m/M (where n is measured in moles, mol. Mass, m, is in grams, g. Molar mass, M, is in g/mol).

For ideal gases only, the forces between particles are _____________.

negligible, meaning that they are small enough to be ignored.

Are gases in group eight reactive? Explain why or why not.

nonreactive or inert due to their complete outer shell

Methane present in the atmosphere is the main component of what? Resulting from what?

of biogas resulting from burning of organic matter. Animals also release methane by farting. Also the melting of permafrost releases it, too because of global warming.

Ask Dad: When they want the factor change of temperature, do they want it in kelvin or degrees Celsius?

Continue from textbook pg. 41: Gases and their technological applications

If the problem doesn't mention a change in variable, just assume that it is constant...

Look at: Combustion of hydrocarbons: https://www.youtube.com/watch?v=pVBsGRrtIRM#t=47 and http://www.ausetute.com.au/combusta.html

Quiz Q: Just be careful that on a graph, if the temperature is in °C, the line will NOT go through (0,0), but will have an x-intercept of -273. If it were to go through (0,0), then the temperature would have to be in Kelvin...

Use R = 0.082 atmL/molK if P is in atm and V is in L...

You can round your molar mass to the nearest whole number...

You can round your molar masses to the nearest whole number when not using sig figs...

You will be given Graham's Law on exams, as well as R = 8.31 kPaL/molK = 0.082 atmL/molK...

The kinetic energy (Ek) of a particle of gas depends on what?

on its mass (m) and velocity (v) because Ek = 1/2mv²

Gases can be monatomic. What does that mean? Give examples.

one atom; He, Ar, Ne

Textbook pg. 51 #17. What gas is responsible for browning the surface of an apple when it is sliced?

oxygen gas.

Workbook: What does kinetic energy result in?

particles of matter within a gas (atoms or molecules) undergo a serious amount of motion as a result of the kinetic energy within them.

All matter consists of what? Explain.

particles; either atoms or molecules

How are a particles' collisions?

perfectly elastic; they bounce back. It's not like they slow down as they collide. They will move at the same speed even when they collide with one another.

Daily Uses of Gases: Gases play an important role in many important natural phenomena including what?

photosynthesis, respiration and climate control.

When the conditions of pressure, volume and temperature are changed, what about matter will change?

physical properties of matter

The greater the number of collisions, the greater the what?

pressure

What do manometers measure?

pressure...

Textbook pg. 51 #6. c. What is the impact of the combustion of hydrocarbons on the environment?

producing hydrogen involves extracting it from methane because methane contains hydrogen, consumes a lot of energy and produces a considerable amount of greenhouse gases. The products of hydrocarbons are carbon dioxide and water vapor. Since carbon dioxide is a greenhouse gas, it will increase Earth's temperature if it is used too much.

When temperature and pressure are constant, the volume that a gas occupies is proportional to what? What law is this?

proportional to the number of particles present. This is Avogadro's Law.

How can the behavior of a gas under new conditions be described?

qualitatively, quantitatively or through simple gas laws.

According to Graham's Law, under identical conditions of temperature and pressure, light gases will diffuse more slowly or quickly than heavy gases?

quickly

The atomic structure of a gas is largely responsible for its what?

reactivity

What does the movement of air on the planet caused by prevailing winds do?

regulates the climate in each region. It also helps to disperse plant pollen.

Daily Uses of Gases: Is nitrogen gas stable?

Yes, very

Is the molar volume ratio relevant for the ideal gas law?

Yes. NOTE: If you ever forget the molar ratios, just do: 1. PV = nRT STP --> 101.3 kPa x V = 1 mol x 8.31 x 273 K V = 22.4 L 2. PV = nRT SATP --> 101.3 kPa x V = 1 mol x 8.31 x 298 K V = 24.5 L

What is combustion?

a rapid form of oxidation in which a fuel releases a lot of energy in a reaction with an oxidizer.

What is cm³?

a unit for volume...

Textbook pg. 51 #5. c. What does methane do?

a very powerful greenhouse gas that is the main component of biogas

Dalton's Law: The partial pressure of CO₂ in a mixture of gases is 0.9 atm. The total pressure of the mixture is 1.2 atm. a) What % of the mixture is carbon dioxide? b) There are a total of 5 moles of gas in the mixture. What mass of carbon dioxide is present?

a) Do a ratio: 100% / x = 1.2 atm . 0.9 atm (since 100% of the pressure is 1.2 atm) x = 75% b) PT / nT = PCO₂ /nCO₂ *The letters and CO₂ following P should be subscripts... 1.2 atm / 5 mol = 0.9 atm / nCO₂ nCO₂ = 3.75 mol OR you could do: 0.75 x 5 mol = 3.75 mol m = n x M m = 3.75 mol x 44 g/mol m = 165 g

What are aurora borealis and australis produced by?

solar wind particles that penetrate the atmosphere close to the magnetic poles and ionize gas particles in the upper atmosphere. These ionized gas particles then release surplus energy they have absorbed by emitting light that is visible in the form of multicolored veils.

Workbook: More about absolute zero.

the Kelvin scale sets its zero at a very extreme condition, called absolute zero. There is indeed something very absolute about this zero, because it's the temperature at which all particles freeze, ceasing all movement. Absolute zero is the lowest possible temperature, representing the complete absence of heat. It's as low as you can possibly go.

The average/mean kinetic energy of the particles of a gas is directly proportional to what?

the absolute temperature...

Electron configuration

the arrangement of electrons in an atom

What is composed of a mixture of various gases that come into play in many natural phenomena?

the atmosphere

What allows liquids to assume the shape of whatever container they are poured in?

their familiar freedom

Why can we state that solids and liquids are virtually incompressible, while gases are compressible?

the forces of attraction between particles in solids and liquids make them virtually (practically) incompressible, so you can't squeeze them together and in gas particles, the forces of attraction are negligible (small enough to be ignored).

When more than two factors (P, V, T, and n) are changed, we make use of what?

the general gas law.

What type of motion do particles in a solid undergo? Is this the only type of motion experienced by this state of matter?

they vibrate, and yes; it is the only type of motion for solids

Graham's Law

v₁/v₂ = √M₂/M₁ (square root applies to both M₂ and M₁) v: velocity; usually m/s, though the units are not important BUT must be consistent M: molar mass

How do you solve stoichiometric problems that involve gases?

we can use the stoichiometric techniques together with the gas laws.

Textbook pg. 51 #5. b. What is N₂?

the main component of the atmosphere

When can we make use of the simply gas laws? What are those factors?

when ONLY two of the factors that influence the behavior of a gas are changed while the others are constant. These factors include P, V, T and n.

What is a vacuum?

the removing of all the air

What is the kinetic energy of a gaseous particle directly proportional to?

the temperature of a gas

What will also affect a gas' reactivity?

the type of bond present in a gaseous molecule

Graham's Law: What will happen to the velocity if the molar mass of a molecule is doubled?

the velocity will be halved since it is an inversely proportional relationship. Velocity is inversely proportional to the SQUARE ROOT OF "M"; not that it is inversely proportional to "M".

How will the square root affect the formula if asked about the inversely proportion part about Graham's Law?

the velocity will be halved since it is an inversely proportional relationship. Velocity is inversely proportional to the SQUARE ROOT OF "M"; not that it is inversely proportional to "M". See Dad's math in chemistry binder which explores that relationship.

When does effusion occur?

when a gas passes through a very small opening

Molar volume: At STP, 1 mol of any gas has a volume of what?

22.4 L... (MEMORIZE...)

What is the molar volume at SATP?

24.5 L/mol (MUST MEMORIZE...)

What is a hydrocarbon?

contains 2 elements: hydrogen and carbon

Always put down your units throughout the formula and in the answer for the simple gas laws.

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Always put your units down for a formula/Law

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Charles' Law and Gay-Lussac's Law: Always convert your temperature to kelvin by adding 273 to your degrees Celsius value.

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For Graham's Law: v₁/v₂ = √M₂/M₁ , divide first, then square root.

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Make sure your chemical equations are ALWAYS balanced! # of atoms in Reactants = # of atoms in Products (for each element)

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Must know about STP and SATP, what they stand for and what's their kelvin and temperature.

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The maximum variation means the difference: Final - Initial.

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Use "ANS" on calculator if the value is something like 33.33333333.... especially for factor of change so that it is accurate.

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What is STP's pressure and temperature?

273 k and and 101.3 kPa

How do animals contribute to the greenhouse effect?

They release methane in the form of flatulence

Gases play an important role in plants. How?

- Photosynthesis - Process of food production for plants through photosynthesis

Textbook Review pg. 50: Gases are used in many natural phenomena. Name them all.

- Photosynthesis - Respiration of living organisms - Greenhouse effect - Aurora borealis and australis - Meteorological phenomena

Describe the graph for Avogadro's Law. What is on the axes? Where does the line start? What is the title? Which quadrant is it and why?

- x axis: # of moles (mol) - y-axis: Volume (L) - Line starts at (0,0) See notes for how the line looks for this law as well as all other laws... - Title: V vs. n (y vs. x) - Only first quadrant because you can't have negative values.

Mnemonic for diatomic molecules...

"I Have No Bright Or Clever Friends" : hydrogen, nitrogen, fluorine, oxygen, chlorine, iodine, and bromine

Name the chemical roles that gases can play. Is this harmful or beneficial for the environment?

- Combustion of methane, hydrogen, propane, etc. in order to be a fuel, heat source, etc. - Oxidation These are harmful for the environment.

Dalton's Law: Describe the relationship.

The partial pressure of a gas is proportional to the number of moles of that gas in the gaseous mixture.

Test Q: A balloon vendor wishes to fill the greatest number of balloons from his helium tank. Each balloon is to have a volume of 2 liters. What would be the best atmospheric conditions to inflate the maximum number of conditions?

- A high temperature results in a greater volume (inflation) since temperature is directly proportional to volume (numerator is directly proportional to denominator...)... This is also Charles' Law... - A low pressure results in an increased volume, since pressure is inversely proportional to volume (numerator is inversely proportional to other numerator)... this is also Boyle's Law...

Explain the following phenomenon using the particle model of matter: A hydroplane can easily fly through a cloud and can also land on the surface of a lake.

- All matter is composed of particles (ions, atoms or molecules) that are infinitely small with more or less space between them depending on their phase. - Particles of matter attract or repel each other, and the force that attracts or repels them from each other varies depending on the distance that separates them

Explain the following phenomenon using the particle model of matter: Fishing on a lake in the winter requires a little more effort since the ice must be broken.

What are examples of diffusion?

- Distribution of perfume where it is sprayed in one part of a room, yet soon you can smell it everywhere. - Movement of a drop of food coloring in a glass of water, where eventually the entire glass will be colored. - Making tea, where molecules from the tea cross the tea bag and spread out into the cup of water. - Shaking salt into water. The salt dissolves and the ions move until they are evenly distributed. - Lighting a cigarette, where the smoke spreads to all parts of a room. - Placing a drop of food coloring onto a square of gelatin, so that eventually the color will spread to a lighter color throughout the block. - Carbon dioxide bubbles diffuse from an open soda, leaving it flat. - If you place a wilted celery stick in water, water will diffuse into the plant, making it firm again.

Propose two actions to counter the effect of carbon dioxide in the greenhouse effect: one in which carbon dioxide is a reactant, and another in which it is involved as a product.

- More plants could be planted, where carbon dioxide is the reactant. Additionally, oxygen is created which decreases carbon dioxide in the atmosphere. - Reducing the amount of vehicules running on combustible gases, wherein carbon dioxide is the product - By decreasing the amount of hydrocarbons that are used as fuels (e.g. cars, heating systems)

Name the biological roles that gases can play. Is this harmful or beneficial for the environment?

- Photosynthesis - Cellular respiration - Nitrogen for plant growth and as a fertilizer - Eutrophication These are beneficial for the environment, except for eutrophication, which is harmful for the environment.

Gases are used in many technological applications. Name them all.

- Welding - In areas of food, agriculture and health, among others.

How is the translational motion of particles different from the other two forms of motion?

- With translation, there's more freedom of movement - In translation, a molecule simply moves in a straight line from one collision to the next, whereas in rotation, a molecule can rotate on the x, y, and z axis. In vibration, there are three modes in which an object can vibrate in: symmetrical and asymmetrical stretching as well as bending.

Textbook pg. 51 #11. Give examples of natural phenomena in which gases play an essential role.

- cellular respiration - photosynthesis - greenhouse gases which trap the heat from the sun - ozone, O₃, which protects us from the sun's UV rays - forest fires - volcanic eruptions

What allows solids to have their own shape and to occupy a defined volume?

- due to the forces that exist between them. - the position of particles results from an equilibrium between these forces - particles cannot slide against each other and change the shape of the solid, since the forces that bind them are very difficult to modify.

Explain why it is important to regularly inspect and maintain a heating system, particularly one that uses natural gas.

- in order for heating to occur, combustion must occur, therefore it is important to make sure that the fuel, oxidizer and the source of ignition is present - to ensure a complete combustion of propane so carbon monoxide isn't formed - gas leaks

Textbook pg. 51 #13. To keep potato chips intact during transport, they are packaged in bags filled with gas. The gas used is not air, but rather nitrogen (N₂). Why is nitrogen rather than air used to inflate bags of chips?

- nitrogen doesn't react easily because of its triple bond, which is harder to break - air would only speed up the decaying process of the chips - nitrogen preserves the freshness of foods in packaging

Why is the use of hydrogen gas as a fuel still very limited?

- producing hydrogen, which involves extracting it from methane, consumes a lot of energy and produces a considerable amount of greenhouse gases

Eutrophication

-process by which lakes, estuaries, and other still bodies of water receive higher than normal levels of nutrients, which results in excessive growth of plants -- an algal bloom

*Always put the states/phases in chemical equations. Example: (g) (s) (l)

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Also put units for factor of change

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Always make sense of your answers for the simple gas laws (so for example if it makes sense that one is greater than the other).

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cm³ to L

1 L = 1000 cm³ (do a ratio like so: 1 L / 1000 cm³ = x L / whatever cm³ the word problem gives you)

At STP, 2 mol has a volume of what?

1 mol = 22.4 L, so 2 mol x 22.4 = 44.8 L (it is a ratio)

Molar mass is the mass of what?

1 mole

Molar volume is the volume of what?

1 mole

m³ into L

1 m³ = 1000 L...

What is the balanced equation for the oxidation of: Mg

1) Do the crossover subscript rule: Remember, oxidation involves oxygen. Mg²⁺ O⁻² ... Crossover subscripts... You end up with: Mg₂O₂, BUT, the subscripts will cancel out since they're the same, leaving you with: MgO (this goes in the products side) 2) Write out the equation Remember that oxidation involves oxygen gas: O₂ (not O) So; Mg + O₂ --> MgO 3) Balance it (if not already balanced)! __ Mg + __ O₂ --> __ MgO Reactants: 2 O Products: 1 O = Mg + O₂ --> 2MgO (Now balance the Mg) = 2Mg + O₂ --> 2MgO

Dalton's Law: A mixture of He, Ne and Ar gases have a total pressure of 105.0 kPa. If there is 15% Ar, 60% He and 25% Ne, what is the partial pressure of each gas?

1. Argon will take up 15% of the total pressure (105.0 kPa), Helium will take up 60% of the total pressure, and Neon will take up 25% of the total pressure... so, convert your percentages to decimals and multiply it with 105.0 KPa...: P(Ar) = 0.15 x 105.0 kPa = 15.75 kPa P(He) = 0.60 x 105.0 kPa = 63 kPa P(Ne) = 0.25 x 105.0 kPa = 26.25 kPa *What's in brackets should be written as a subscript... If you add them all together: 15.75 kPa + 63 kPa + 26.25 KPa, then it should equal the total, = 105.0 kPa.

In what three ways do particles vibrate?

1. Bending 2. Asymmetric stretching; uneven stretching in/out 3. Symmetric stretching; even stretching in/out See my textbook homework drawing!

QC Learn: Gases are used for different purposes such as: 1)Disinfection 2)Air conditioning 3)Energy Production In order, which gases serve the purposes listed above? 1. Nitrogen 2. Oxygen 3. Chlorine 1. Chlorine 2. Freon 3. Methane 1. Methane 2. Nitrogen 3. Carbon Dioxide 1. Oxygen 2. Freon 3. Carbon Dioxide

1. Chlorine 2. Freon (a compound...) 3. Methane Here, just go by process of elimination.

A 25.0 mL sample of oxygen is collected at a temperature of 90 K and a pressure of 100 kPa. What volume will the oxygen have when its temperature reaches 75 kPa? By what factor did the pressure change? What's the factor of change for the volume?

1. Collect your data: V = 25.0 mL T = 90 K P = 100 kPa T = 75 kPa V = ? Since it is asking for volume, and the only gas law that has both volume and pressure is Boyle's Law: P₁V₁ = P₂V₂. It is not Gay-Lussac's law because it doesn't have volume in it and that's what the question is asking for. 2. Use the formula. Always put down your units! Isolate. P₁V₁ = P₂V₂ ^Initial = ^ Final (easiest way to think of it) 100 kPa x 25 mL = 75 kPa x V₂ V₂ = 33.333333... mL Here you see that as pressure decreases, the volume will increase. The numbers show this. 3. Factor of change = Final value / Initial value (for the pressure) 75 kPa . 100 kPa = 0.75 BUT it is preferred that you put into fraction form so you could see that volume and pressure are inversely proportional: 3/4 4. Factor of change = Final value / Initial value (for the volume) 33.3333 mL/24.0 mL = 1.33333.... or 4/3. Notice how the fractions are flipped? That's because the factors (pressure and volume) are inversely proportional.

Test Q: A weather balloon is filled with 200 L of helium at a temperature of 23°C and a pressure of 98.3 kPa. After the balloon rises 12 km into the stratosphere, the temperature decreases to -60°C and the pressure decreases to 0.112 kPa. What will be the new volume of the weather balloon?

1. Compile your data V1 = 200 L T1 = 23 + 273 = 296 k P1 = 98.3 kPa T2 = -60 + 273 = 213 k P2 = 0.112 kPa V2 = ? The formula used is not something we've learned! We can't solve it using Charles' Law because pressure is NOT a constant in this problem! This was a trick question!

Textbook example pg. 79: A sample of helium (He) gas is collected at ambient temperature in a 2.5 L elastic rubber ball at normal atmospheric pressure. The ball is then immersed in a container of water, also at room temperature, such that the external pressure exerted on its walls increases to 110.6 kPa. What is the final volume of the ball?

1. Compile your data: "ambient" temperature-- it is SATP because SATP stands for Standard AMBIENT TEMPERATURE and pressure T₁/₂ = will stay constant at 298 k, because room temperature is also 298 k V₁ = 2.5 L P₁ = at normal atmospheric pressure, that is 1 atm = 101.3 kPa P₂ = 110.6 kPa V₂ = ? 2. Use Boyle's Law: P₁V₁ = P₂V₂ 101.3 kPa x 2.5 L = 110.6 kPa x V₂ V₂ = 2.3 L is the final volume of the ball

The pressure of a gas at 100 kPa rises from 20 degrees Celsius to 85 degrees Celsius. What is its new pressure?

1. Compile your data: P₁ = 100 kPa T₁ = 20 degrees Celsius + 273 k = 293 k T₂ = 85 degrees Celsius + 273 k = 358 k 2. Since we're missing P₂, we use Gay-Lussac's Law: P₁ / T₁ = P₂ / T₂ 100 kPa/ T₁ = P₂ / 293 k = P₂ / 358 k P₂ = 122 kPa

Textbook pg. 98 #21. A ball is filled with a given of hydrogen (H₂) at 22°C. The volume of the ball is 18.4 L at this point. The ball is then submerged in water and its volume increases by one quarter. What is the temperature of the water?

1. Compile your data: T1 = 22 degrees + 273 K = 295 k V1 = 18.4 L V2 = increases by one quarter... 18.4 x 1/4 = 4.6, 18.4 + 4.6 = 23 L T2 = ? 2. Use Charles' Law: V₁/T₁ = V₂/T₂ 18.4 L / 295 k = 23 L / T2 T₂ = 368.75 k

A gas at 200 K occupies 1.45 L. What volume does it occupy at 250 k? What do you notice about the new volume?

1. Compile your data: T₁ = 200 K V₁ = 1.45 L T₂ = 250 k V₂ = ? 2. Use the formula, Charles' Law, and isolate: V₁/T₁ = V₂/T₂ Initial = Final 1.45 L / 200 K = V₂ / 250 K V₂ = 1.8125 L Notice how V₂ is bigger because temperature is greater and they're proportional, so the new volume will also be greater.

What are the different behaviors of gases?

1. Compressibility 2. Expansion 3. Diffusion, Effusion (Graham's Law)

Test Q: Last winter, the internal pressure for the tires on a car was set at 175 kPa when the temperature was -30°C. According to the manufacturer's recommendations, the internal pressure for these tires should not exceed 250 kPa. The following summer, the wheels on this car were misaligned. Given this defect and the relatively high temperature of the asphalt on the roads in the summer, the temperature of the tires could have risen above 85°C. If the temperature of the tires reaches 85°C, will the internal pressure correspond to the manufacturer's recommendation? Explain your answer.

1. Convert right away to kelvin -30 + 273 = 23 k 85 + 273 = 358 k 2. Compile your data: P1 = 175 kPa T1 = 23 k P2 = ? It is not 250 kPa because we need to check if the internal pressure exceeds 250 kPa and will thus correspond to the manufacturer's recommendation. T2 = 358 k 3. Use Gay-Lussac's Law: P₁ / T₁ = P₂ / T₂ 175 kPa / 23 k = P2 / 358 k P2 = 257.83 kPa 4. Answer: Since the internal pressure exceeds 250 kPa, no, it will not.

Textbook example pg. 83: A 28.7 mL sample of oxygen gas is collected in a glass syringe at SATP. The syringe is placed in an oven at 65°C until the gas attains the temperature of the oven. What volume will the oxygen occupy if the atmospheric pressure in the oven is the same as outside the oven? If the syringe can contain a volume of 50 mL, will the mobile piston be able to retain the gas inside?

1. Convert right away to kelvin: 65°C + 273 k = 338 k At SATP... that's 298 k 2. Compile your data: V₁ = 28.7 mL T₁ = 298 k V₂ = is what we need to find because we need to find out if the mobile piston will be able to retain the gas inside T₂ = 338 k Since they say the atmospheric pressure will be constant, we do not use Boyle's Law, nor Gay-Lussac's Law. 2. Use Charles' Law: V₁/T₁ = V₂/T₂ 28.7 mL /298 k = V₂/338 k V₂ = 32.6 mL Answer: yes, since V₂ is lower than 50 mL, the mobile piston will be able to retain the gas inside.

Molar Volume: What volume is occupied by 40 g of methane gas, CH₄, at STP?

1. Find the number of moles of methane gas: n = m/M = 40 g/16 g/mol (always indicate your units throughout your formula and in final answer...) = 2.5 mol CH₄ 2. Since it says STP, simply do the molar volume ratio: 22.4 L/1 mol = x L/2.5 mol = 56 L

Stoichiometry: Potassium, K, oxidizes to form potassium oxide, K₂O. If 19.5 g of potassium are oxidized, what mass of potassium is formed? 4K + O₂ → 2K₂O

1. Find the number of moles of potassium: n = m/M = 19.5 / 39 = 0.5 mol K 2. Use molar ratio: From balanced equation Your calculations 4 mol K / 2 mol K₂O = 0.5 mol K / x mol K₂O x = 0.25 mol K₂O 3. Solve the problem: m = n x M = 0.25 mol x 94 g/mol = 23.5 g of K₂O

Stoichiometry and Gas Laws: Potassium, K, oxidizes to form potassium oxide, K₂O. If 19.5 g of potassium are oxidized at STP, what volume of oxygen gas, O₂, is consumed? 4K + O₂ → 2K₂O

1. Find the number of moles of potassium: n = m/M = 19.5 g / 39 g/mol = 0.5 mol of K. 2. Use molar ratio: 4 mol K/1 mol 0₂ = 0.5 mol K / x mol O₂ = 0.125 mol of O₂ 3. Solve the problem. We will use n = PV/RT because we're given STP. Plug in your info: V = 0.125 mol x 8.31 kPaL/molK x 273 K / 101.3 kPa V = 2.8 L Or, since you're given STP, and as a recap from molar volume: STP --> 22.4 L/mol, we can do a MOLAR VOLUME RATIO...: 22.4 L / 1 mol = x / 0.125 mol = 2.8 L

Test Q: Nitro-glycerine, C₃H₅(ONO₂)₃, has a density of 1.59 g/mL. When it explodes, the following reaction takes place: 4 C₃H₅(ONO₂)₃ → 12 CO₂ + O₂ + 6N₂ + 10 H₂O What volume of water vapor, measured at STP, is produced when 100 mL of nitro-glycerine explodes?

1. Identify your variables d = 1.59 g/mL STP: P = 101.3kPa, T = 273 K 2. Isolate for g: 1.59 = x g/100 mL x = 159 g 3. Solve for the number of moles: n = m/M n = 159 g/227.0865 g/mol n = 0.7 mol 3. Do the molar ratio: 4 C₃H₅(ONO₂)₃ / 0.7 mol = 10 H₂O / x x = 1.75 mol 4. Molar volume ratio (because it's STP): 1 mol / 22.4 L = 1.75 mol / x x = 39.2 L of water vapor (Ask Dad if correct)

Test Q: A 7.6 L tank, fitted with a manometer, contains an unknown gas. We vary the temperature and then determine the pressure of the gas. The graph shows the result (basically it is a line passing through zero: we have the following points: (250, 400), (275, 450), (300, 500), (325, 550), where on the x-axis it shows temperature (in Kelvin), and on the y-axis it shows pressure (in kPa) If the tank is stored at a temperature of 27°C and it contains 26 g of gas, identify the gas from among the following. H₂, NH₃, N₂, CO₂, SO₂, Cl₂

1. Identify your variables: Initial... V= 7.6 L From a point of the graph, we can obtain: T (K) = 300 K P = 500 kPa We will NOT use the general gas law because we don't have enough information, not even if were to cancel out. So therefore we must use the ideal gas law: PV = nRT P = 500 kPa V = 7.6 L n = ? R = 8.31 kPaL/molK T = 300 K Isolate for n: n = PV/RT n = 500 kPa x 7.6 L / 8.31 kPaL/molK x 300 K n = 1.52 mol of an unknown gas Then we can solve for the molar mass to help identify our gas...: M = n/M M = 1.52 mol / 26 g M = 17.1 g/mol You'd calculate all the molar masses of the gases given, and see that M = 17.1 g/mol matches up with NH³ N x molar mass of N found on PT 3 x molar mass of H found on PT = 17.1 g/mol

Test Q: A science student would like to identify a pure gas sample. She finds the following info: Mass of empty container: 4.40 g Mass of container + Unknown gas: 6.00 g Volume: 1210 mL Temperature : 18°C Pressure: 102 kPa Which of the following is the unknown gas? H₂ O₂ OCl₂ BCl₃

1. Identify your variables: Mass of gas = 6.00 g - 4.40 g = 1.6 g V = 1210 mL T = 291 K P = 102 kPa 2. PV = nRT 102 kPa x 1.21 L = n x 8.31kPaL/molK x 291 K To get an accurate number of moles, you must convert the 1210 mL into L because the constant R, uses L... n = 0.05 mol 3. Find the mass of each gas to see which one matches up to 1.6 g: H₂: m = n x M, m = 0.05 x 2 g/mol = 0.1 g O₂: m = 0.05 x 32 g/mol = 1.6 g, so it's O₂. You could've also calculate the molar mass of each gas, then do 0.05 = 1.6 g/M and see which gas the M matches up to. Would get the same answer.

Test Q: A sample of silicon tetrachloride vapour (SiCl₄) was obtained at 95.2 kPa pressure and a temperature of 250°C. Determine the density of that sample in g/L under the given conditions.

1. Identify your variables: P = 95.2 kPa T = 250°C + 273 K = 523 K M = 168 g/mol Since it's SiCl₄ (an invisible coefficient of 1: 1 SiCl₄, it's one mole. On the test, you should have teacher confirm whether that is the case...) Therefore, n = 1 mol V = nRT/P V = 1 mol x 8.31 kPaL/molK x 523 K / 95.2 KPa V = 45.65 L Since density = m/v...., then calculate the mass of SiCl₄: m = n x M m = 1 mol x 168 g/mol m = 168 g of SiCl₄ d = m/v... d = 168 g / 45.65 L d = 3.68 g/L...

Test Q: At SATP, you heat ammonium nitrate (NH₄NO₃) and obtain 27 g of water (H₂O) and laughing gas (N₂O). Equation for the reaction: NH₄NO₃ → 2H₂O + N₂O What volume of laughing gas will be produced?

1. Identify your variables: SATP → 101.3 kPa (P), 298 K (T) m = 27 g V (of laughing gas) = ? Since they're giving you info for one thing and asking you to solve for another, this will involve a stoichiometric ratio. Since they are not describing a change, we will use the ideal gas law: PV = nRT 2. Find the number of moles for water n = m/M = 27 g / 18 g/mol m = 1.5 mol of H₂O 3. Use a molar ratio: 2 mol H₂O / 1.5 mol H₂O = 1 mol N₂O / x mol N₂O x = 0.75 mol of N₂O 4. PV = NRT 101.3 kPa x V = 0.75 mol x 8.31 KPaL/molK OR, since they mention SATP, you could do molar volume ratio (easier): 1 mol / 24.5 L = 0.75 mol / x L x = 18.375 L

Test Q: At 35⁺C, a gas occupies a volume of 250 mL at a pressure of 101.3 kPa. After heating this gas, you notice that it occupies a volume of 275 mL at a pressure of 121.2 kPa. What temperature CHANGE has the gas undergone?

1. Identify your variables: T1 = 35 + 273 K = 308 K V1 = 250 mL P1 = 101.3 kPa V2 = 275 mL P2 = 121.2 kPa T2 = ? So use the general gas law and cancel out the n1 and n2's. Plug them all in and isolate T2. You should get T2 = 405.4 K.

Test Q: A 34.0 mL cylinder is filled with oxygen. The valve placed on the cylinder is defective, and as result, the oxygen slowly escapes. On Monday morning, the lab technician registered a pressure of 4.52 x 10² kPa and a temperature of 23.0°C. After four days the pressure decreased to 4.02 x 10² kPa and the temperature was 18.0°C. What mass of oxygen gas escaped from the cylinder during the four day period?

1. Identify your variables: V1 = 34.0 mL P1 = 4.52 x 10² kPa T1 = 296 K P2 = 4.02 x 10² kPa T2 = 291 K V2 = ? 2. n = PV/RT n = 452 kPa x 34.0 mL/8.31 kPaL/molK x 296K n = 6.2 mol of O₂ 3. m = n x M m = 0.198 g of O₂ 4. Since the volume is constant, V2 will also = 34 mL. P2 and T2 will only change: n = PV/RT n = 4.02 x 10² kPa x 34 mL / 8.31 x 291 K n = ... (and then do m = n x M) We have to use PV = nRT in order to get the number of moles... Use n = PV/RT for both the initial and final. Then calculate the differences of the masses to see how much escaped from the cylinder.

Quiz Q: A 5.0 L vessel contains 2.0 mol of iodine gas, I₂, at 20°C. The Celsius temperature of the gas is doubled and the pressure remains constant. Determine the density of the gas under the NEW conditions.

1. Identify your variables: V1 = 5.0 L V2 = The vessel changes volume, and that is our unknown... T1 = 30 + 273 = 293 K T2 = 20 x 2 = 40 + 273 K = 313 K Use V1/T1 = V2/T2 d = m/v 2. Determine the mass of I₂: m = n x M m = 2.0 mol x 253 g/mol m = 506 g 3. V1/T1 = V2/T2 --> 5 L / 293 K = V2 / 313 K V2 = 5.34 L 4. p = m/v, p = 506 g / 5.34 = 95.06 g/L Here the volume is not constant because the temperature change will have an effect on the volume. Temperature and volume are directly proportional.

Test Q: Hummingbirds have an extremely rapid metabolic rate. In order to maintain it, they must consume approximately one third their body mass in sugar every day. Energy is produced when sugar is broken down during cellular respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy If a hummingbird burns 1.00 gram of sugar, C₆H₁₂O₆, during cellular respiration, what is the volume of CO₂ produced at 37°C and 101.3 kPa?

1. Identify your variables: m = 1 g V = ? T = 37 + 273 = 310 K P = 101.3 kPa 2. Solve for number of moles of sugar: n = m/M n = 0.006 mol 3. Do a molar ratio: 1 mol C₆H₁₂O₆ / 6CO₂ = 0.006 mol C₆H₁₂O₆ / x x = 0.036 mol CO₂ 4. PV = nRT 101.3 kPa x V = 0.036 mol x 8.31 kPaL/molK x 310 K V = 0.92 L

Test Q: Two identical balloons were filled at the same temperature. The first contains 10 g of nitrogen gas, N₂, and the second, 5 g of hydrogen gas, H₂. In which balloon is the pressure greater? Explain your answer.

1. Identify your variables: m of N₂ = 10 g m of H₂ = 5 g 2. Calculate the number of moles for both: n = m/M = 10 g / 28 g/mol = 0.36 mol of nitrogen gas n = m/M = 5 g/2 g/mol = 2.5 mol of H₂ 3. Since pressure and the number of moles are directly proportional to each other (denominator directly proportional to numerator in the general gas law...), then the 2.5 mol, H₂, has a greater pressure. More moles = more collisions = greater pressure.

An unknown gas takes 192 seconds to effuse through a porous barrier, while the same volume of nitrogen (N₂) effuses across the same barrier in 84 seconds. The conditions of temperature and pressure are identical for the two gases. What is the molar mass of the unknown gas?

1. Notice how temperature and pressure are constants, so we use Graham's Law because T and P are excluded from the formula and we're also dealing with time. v₁/v₂ = √M₂/M₁ 2. The 192 seconds and 84 seconds is NOT a rate, it is a time. In order to convert it to m/s, we put it as: x / 192 and x/84. The "x" will represent the # of meters in those 192 and 84 seconds. 3. v₁/v₂ = √M₂/M₁ x/192 / x/84 = √28 g/mol/M₁ You may enter it in your calculator as... 1/192 ÷ (1/84) (7/16)² = 28 g/mol/M2 Or Convert it to decimal so that it is easier to square root... 0.4375² = 28 g/mol/M2 0.19 = 28 g/mol/M2 Cross multiply... = 146.29 g/mol of the unknown gas Ask Dad how we would get the # of meters (if it is possible)?

Test Q: A sample of carbon tetrachloride vapor (CCl₄) was obtained at 95.2 kPa pressure and a temperature of 125°C. Determine the density of that sample in g/L under the given conditions.

1. P = 95. 2 kPa T = 125 + 273 = 398 K d = ? g/L n = 1 mol (Ask Dad; again, why 1 mol?) 2. PV = nRT 95.2 kPa x V = 1 mol x 8.31kPaL/molK x 398 K V = 34.74 L 2. m = n x M m = 1 mol x 152 g/mol m = 152 g 3. d = 152 g/34.74 L = divide... = 4.37 g/mol = d If they gave you 152 g/0.03474 mL, then just change mL to L by multiply by 1000, then just divide...

Draw a model representing fluorine gas using a Lewis diagram.

1. The Lewis shows the number of valence electrons. So draw two Fluorines, F₂, which means two fluorines, making sure that it has seven valence electrons. 2. Since they both need one other electron to complete their shell, they will share electrons because two non-metals form a covalent bond, so they will SHARE. 3. Every pair shared represents ONE bond. They shared ONCE since 8-7=1, so it's a SINGLE BOND. 4. Represent the single bond as such: F - F

Draw a model representing nitrogen gas using a Lewis diagram.

1. The Lewis shows the number of valence electrons. So draw two nitrogens; N₂, which means two nitrogens, making sure that it has five valence electrons. 2. Since they both need 3 other electrons to complete their shell, they will share electrons because two non-metals form a covalent bond, so they will SHARE. 3. Every pair shared represents ONE bond. They shared THREE TIMES since 8-5=3, so it's a TRIPLE BOND. 4. Represent the triple bond as such: N (triple bond symbol, which is just three horizontal dashes) N

Draw a model representing oxygen gas using a Lewis diagram.

1. The Lewis shows the number of valence electrons. So draw two pxygens; O₂, which means two oxygens, making sure that it has six valence electrons. 2. Since they both need two other electrons to complete their shell, they will share electrons because two non-metals form a covalent bond, so they will SHARE. 3. Every pair shared represents ONE bond. They shared TWO TIMES since 8-6=2, so it's a DOUBLE BOND. 4. Represent the double bond as such: O = O

Determine the products of the reaction below. Balance the resulting chemical equation. CH₄ + O₂

1. This is a combustion reaction because we have CH₄ (CARBON and HYDROGEN) 2. The products of a combustion reaction are: CO₂ + H₂O 3. CH₄ + O₂ --> CO₂ + H₂O CH₄ + 2O₂ --> CO₂ + 2H₂O

Determine the products of the reaction below. Balance the resulting chemical equation. C₂H₄ + O₂

1. This is an oxidation reaction because of O₂. This is ALSO a combustion reaction because we have CARBON and HYDROGEN (C₂H₄). The products for this type of reaction is: carbon dioxide and water. So it's: C₂H₄ + O₂ --> CO₂ + H₂O 2. Balance it: C₂H₄ + O₂ --> 2CO₂ + H₂O C₂H₄ + O₂ --> 2CO₂ + 2H₂O C₂H₄ + 3O₂ --> 2CO₂ + 2H₂O

Txtbk p. 98 #35: An elastic rubber balloon is inflated with 0.0784 mol of carbon dioxide until it reaches a volume of 1.76 L at STP. How many moles of carbon dioxide must be added to the balloon for its volume to attain 1.98 L under the same conditions? Explain what would happen, if instead of adding carbon dioxide to the already inflated balloon, helium was added to increase the volume.

1. Write down what you're given n1 = 0.0784 mol V1 = 1.76 L V2 = 1.98 L STP is constant, so we only use this formula: V1/n1 = V2/n2 2. Apply the formula, you get: n2 = 0.0882 3. How many moles of carbon dioxide added... simply calculate the difference...: n2 - n1, 0.0882 - 0.0784 = 9.8 x 10⁻³ mol or, move the decimal to the left 3 times...: 0.0098 mol 4. Nothing would happen because as long as temperature and pressure are constant, V and n are proportional. So if helium was added to to increase the volume, then the number of moles would increase, too.

Test Q: A cylinder of oxygen (O₂), is left in a hot car. The cylinder has a volume of 10 L and contains 5 moles of oxygen. If the cylinder can withstand a pressure of 20.7 atm, what is the highest Celsius temperature to which the cylinder can be safely exposed?

1. Write down your info: V = 10 L n = 5 moles P = 20.7 atm 2. Since the problem doesn't mention a change in variables, we can use the ideal gas law since the ideal gas law is used when there's no initial/final conditions...: PV = nRT 20.7 atm x 10 L = 5 mol x 0.082 atmL/molK x T T = 504.8 K - 273 K = about 232 degrees Celsius

Test Q: A balloon is filled with an ideal gas and the initial pressure is recorded. Then, the absolute temperature is tripled, the volume is tripled, and the number of moles is tripled. What best describes the final pressure of the gas?

1. Write down your variables: P1 V1 n1 T1 T2 = 3T1 V2 = 3VI N2 = 3N1 2. Plug into formula: P1V1/n1T1 = P2x3V1/3N1x3T1 Cancel out what's common... you cancel out the V1's, the N1's and the T1's because it's like saying V1=V1... If you cancel out the 3's, you're still left with P2/3... P1 = P2/3 Cross multiply... P2=3P1 So the pressure will be tripled as well...

Show what happens to the charge on the chlorine atom during the oxidation of methane by chlorine gas.

1. Write out the reaction. We know that an oxidation reaction requires an oxidizer. Since the problem wants to know what will happen to the charge on the chlorine atom, we know methane is going to react with C₂. The reactants therefore are: CH₄ + Cl₂ The product is going to form a compound. To determine the compound, we just do the crossover subscript rule. Remember that the oxidizer will accept electrons from the substance undergoing oxidation, which is methane in this case. Also remember from last year that chlorine is in group 7, hence the charge is -1. It is also accepting electrons, thus the charge is going to become more negative. Because we have methane, the products won't be the same. The hydrogens in CH₄ will have to go to the products. So just focus on Carbon as you're doing the crossover subscript rule. Carbon is in group 4, hence the charge will be +/-4. But since in this case the carbon is giving away electrons to the Chlorine gas, it has a charge of +4, therefore the carbon is becoming more positive. Hence we do: C⁴⁺ Cl⁻¹ ...Crossover subscript rule... CCl₄ Therefore you have the following chemical equation: CH₄ + Cl₂ → CCl₄ + H₂ So in the reactants, the charge on chlorine gas is 0 (no charge because it is in its elemental form). Simply look at the periodic table and find out what group the oxidizer is in to determine the charge before/after oxidation. Then, balance your equation! Make sure your equations are ALWAYS balanced. It is not in this case. You could tell because we're missing two hydrogens and two chlorines. Therefore the balanced equation is: CH₄ + 2Cl₂ → CCl₄ + 2H₂

Show what happens to the charge on the fluorine atom during the oxidation of magnesium metal by fluorine gas.

1. Write out the reaction. We know that an oxidation reaction requires an oxidizer. Since the problem wants to know what will happen to the charge on the fluorine atom, we know magnesium is going to react with F₂. The reactants therefore are: Mg + F₂ The product is going to form a compound. To determine the compound, we just do the crossover subscript rule. Remember that the oxidizer will accept electrons from the substance undergoing oxidation, which is magnesium in this case. Also remember from last year that fluorine is in group 7, hence the charge is -1. It is also accepting electrons, thus the charge is going to become more negative. Magnesium is in group 2, hence the charge will be +2. In this case, the magnesium has a charge of +2 because it is giving away electrons to the fluorine gas, therefore the magnesium is becoming more positive. Hence we do: Mg²⁺ F⁻¹ ...Crossover subscript rule... MgF₂ Therefore you have the following chemical equation: Mg + F₂→ MgF₂ So in the reactants, the charge on fluorine gas is 0 (no charge because it is in its elemental form). Simply look at the periodic table and find out what group the oxidizer is in to determine the charge before/after oxidation.

Show what happens to the charge on the oxygen atom during the oxidation of silicon by oxygen gas.

1. Write out the reaction. We know that an oxidation reaction requires an oxidizer. Since the problem wants to know what will happen to the charge on the oxygen atom, we know silicon is going to react with O₂. The reactants therefore are: Si + O₂ The product is going to form a compound. To determine the compound, we just do the crossover subscript rule. Remember that the oxidizer will accept electrons from the substance undergoing oxidation, which is silicon in this case. Also remember from last year that oxygen is in group 6, hence the charge is -2. It is also accepting electrons, thus the charge is going to become more negative. Silicon is in group 4, hence the charge will be +/- 4. In this case, the silicon has a charge of +4 because it is giving away electrons to the oxygen gas, therefore the silicon is becoming more positive. Hence we do: Si⁴⁺ O²⁻ ...Crossover subscript rule... Si₂O₄ Reduce your subscripts (divide them by 2), and you get: SiO₂ Therefore you have the following chemical equation: Si + O₂ → SiO₂ So in the reactants, the charge on oxygen gas is 0 (no charge). Since the oxidizer (oxygen gas in this case) accepts electrons from silicon, the charge on oxygen gas will become -2. Simply look at the periodic table and find out what group the oxidizer is in to determine the charge before/after oxidation.

How to convert 1.59 g/mL to g/L...

1.59 g/0.001 L (in 1 mL) = x g / 1 L x = 1590 g divided by 1 = 1590 g/L

What is the pressure and temperature for SATP?

101.3 Kpa, 298K, according to the textbook

How do we convert from one pressure unit to another?

101.3 kPa = 1 atm

What is the equivalent of all units of pressure?

101.3 kPa = 700 mm Hg = 1 atm...

An initial volume of 2 L is reduced by 1/3. Find out the final volume...

2 x 1/3 = 2/3 2 - (2/3) = 1.333333 L

A container possesses 3L internal volume. This volume is divided equally in two by a gas-tight seal. On one half of the seal, neon gas resides at 5 atm. The other half of the container is kept under vacuum. Suddenly and with great fanfare, the internal seal is broken. What is the final pressure within the container?

2.5 atm. Under the initial conditions, gas at 5 atm resides in a 1.5L volume. When the seal is removed, the entire 3L of the container becomes available to the gas, which expands to occupy the new volume. Predictably, its pressure decreases. To calculate the new pressure, P2, plug in the known values and solve: P2 = (5 atm × 1.5L) / 3L = 2.5 atm The final volume is 3 L because at first, the initial temperature is 1.5 L since the volume is split in half. But once the seal breaks, the final volume is 3 L. The pressure at 1.5 L is 5 atm, as they say, and vacuum means that the pressure is 0 atm... So, V1 = 1.5 L, P1 = 5 atm and V2 = 3 L. Plug this into the P1V1 = P2V2 (Boyle's Law) formula.

What is velocity?

A RATE of speed. Example: m/s, not just meters (or seconds)

Electrolysis

A process where electrical energy causes a chemical reaction

The properties of a gas can be altered by changing what conditions? The relationship between the variables are described in what?

A. Pressure, P B. Volume, V (upper-case V) C. Temperature, T (upper-case T) D. Quantity of gas (# of moles, n) The relationship between the variables are described in the simple gas laws.

What are three important points from the particle model of matter?

According to this model: - All matter is composed of particles (ions, atoms or molecules) that are infinitely small with more or less space between them depending on their phase. - Particles of matter attract or repel each other, and the force that attracts or repels them from each other varies depending on the distance that separates them - Particles of matter are always moving

What is the lowest temperature possible?

Absolute 0 (i.e. 0 kelvin); Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion

Gay-Lussac's Law: What is the relationship?

Absolute temperature is directly proportional to pressure.

What is the name of group 1 in the PT?

Alkali metals, except for hydrogen, which is considered a non-metal

What is the name of group 2 in the PT?

Alkaline Earth metals

What is ∝ ?

Alpha symbol- is "directly proportional to". For inversely proportional, it's, for example: P ∝ 1/V

What must you always remember when writing chemical equations?

Always make sure the chemical equations are balanced.

What is an ideal gas?

An ideal gas is a theoretical gas composed of many randomly moving point particles that do not interact except when they collide elastically.

What is an ideal gas? What behaviors must they exhibit?

An ideal gas is any gas that exhibits the following behaviors: 1. All collisions between atoms or molecules are perfectly elastic, meaning that they bounce back/rebounds. They also retain their kinetic energy. 2. There are no intermolecular attractive forces.

Describe Gay-Lussac's Law.

An increase in temperature results in an increase in a molecule's kinetic energy and velocity. If molecules are moving faster, then the force of their impact upon colliding with another molecule will increase as well. As temperature increases, the number of collisions increase, and so pressure increase (pressure is the amount of force exerted on a given area). A decrease in temperature results in a decrease in a molecule's kinetic energy and velocity. If the molecules are moving slower, then the force of their impact upon colliding with another molecule will decrease. As temperature decreases, the number of collisions decrease, and so pressure decreases.

What is the effect of pressure on states?

As temperature and pressure change, an element can be pushed over the boundary from one phase to another. Typically, low temperatures and high pressures promote solid forms, and high temperatures and low pressures promote gaseous forms. Liquids occupy the middle ground. High pressure causes heat to be released. If you compress a gas, it gets hot and tries to lose heat for pressure to go down. If you have a hot cylinder, the heat is going to escape from it because the gas is going to cool down. If you compress the gas, after loosing the heat, it could turn into a liquid or solid. It looses the heat to the environment. Tends to become a liquid or solid. Now you made it so dense that the molecules don't have much room and they will behave like molecules like a liquid or solid. That's how you get liquid nitrogen from nitrogen gas. That's also how you get dry ice from carbon dioxide from compressing carbon dioxide. Similarly, if you cool it down without compressing it it will turn into a liquid or solid. When you compress, the temperature could still be the same as the room but it has lost heat.

Explain Boyle's Law.

As the volume of a gas decreases, gas particles move closer to one another. The number of collisions will increase and this increases the pressure. Also, as the volume of a gas increases, gas particles are further apart. The number of collisions decreases and so does the pressure.

At the same temperature, how would the pressure of an ideal gas differ from that of a gas with mutually attractive particles? How would it differ from that of a gas with mutually repulsive particles?

At a given temperature, an ideal gas would exert greater pressure than a gas with mutually attractive particles and lower pressure than a gas with mutually repulsive particles. On average, mutual attraction allows particles to occupy a smaller volume at a given kinetic energy (since they're going to want to stick together), while mutual repulsion causes particles to attempt to occupy a larger volume (since they're going to be farther apart)

What are ions?

Atoms that gain or lose electrons in an attempt to complete their outer shell.

Chem Wkbk: The 0.80L container from the example question breaks a seal. Because the container stored a poisonous gas, it was itself stored within a larger, vacuum-sealed container. After the poisonous gas expands to fill the newly available volume, the gas is at STP. What is the total volume of the secondary container? The example question: A 0.80L container holds 10 mol of helium. The temperature of the container is 10°C., the internal pressure was solved to be 290.075 atm.

Because this question involves a change, we use the general gas law... P1 = 290.075 atm V1 = 0.8 L n1 = 10 mol (constant) T1 = 283 K P2 = 1.1 atm... V2 = ? n2 = 10 mol (constant) T2 = 273 K Use PV = nRT only to find the conditions at ONE time.

In Boyle's Law, what must be constant?

Constant means roughly the same (doesn't change). Temperature and the number of moles must be constant for Boyle's Law.

What's the difference between Dalton's Law and Dalton's Law of partial pressure?

Dalton's Law: P(total) = P(a) + P(b) + P(c)... PT = total pressure of the mixture PA, PB, PC: partial pressure for each individual gas in the mixture. The letters following P must be subscripts and are usually replaced by elements/compounds... , which states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each of the component gases Dalton's Law of partial pressure: PT / nT = PA/nA = PB/nB = ... , which states that the partial pressure of a gas is proportional to the number of moles of that gas in the gaseous mixture.

How do we convert from Celsius to Kelvin?

Degrees in Celsius + 273 = Kelvin temperature (MUST KNOW...)

What is diffusion? (Workbook definition)

Diffusion is the movement of a substance from an area of higher concentration to an area of lower concentration. Diffusion occurs spontaneously, on its own. Diffusion leads to mixing, eventually producing a homogenous mixture in which the concentration of any gaseous component is equal throughout an entire volume. Of course, that state of complete diffusion is an equilibrium state; achieving equilibrium can take time.

Noble gases have how many valence electrons? What is the exception?

Eight valence electrons, except for helium, which has just 2 valence electrons.

When temperature goes on the x-axis, is it in Celsius or kelvin?

Either. If it is in degrees Celsius, then the x-intercept is -273. Ask Dad how the "k" would change when getting two points? Would we convert the slope to kelvin or the values of the two points? Answer: Yes, wouldn't matter whether you convert the x and y values or just the slope to kelvin because you're still adding 273.

What is the formula for kinetic energy?

Ek = 1/2mv² Ek is the kinetic energy, measured in Joules m is the Molar Mass of the element or compound v is the velocity; will never be asked to solve for velocity

What group is halogens in?

Group 7!

Daily Uses of Gases: Technological application of gases: How are gases used for food preservation?

Filling cereal bags with different types of gas to preserve food. Oxygen only speeds up decaying process.

Formula for factor of change

Final Value / Initial Value = Factor of Change

Which of the following gases is the most chemically reactive? NitrogenHeliumFluorineI don't know.Neon

Find out the type of bond for each using a Lewis Dot diagram. Helium and Neon won't be reactive at all because they're inert gases. Nitrogen will have a triple bond, so it is not as chemically reactive as fluorine. Fluorine, because of its single bond, is more reactive.

Which of the following statements is false according to the kinetic theory of gases? Gas particles have a kinetic energy that is proportional to their temperature. Gas particles are minuscule compared to the size of the container that they are in. Gas particles are spread out so that they are far away from each other. Gas particles always move in an upward direction

Gas particles have a kinetic energy that is proportional to their temperature: true Gas particles are minuscule compared to the size of the container that they are in: true; particles are infinitely small Gas particles are spread out so that they are far away from each other: true Gas particles always move in an upward direction: False; they can also move in a downward direction so long as they move in a translational, rotational and vibrational motion

Explain gas particles with kinetic energy.

Gas particles have a lot of kinetic energy, and constantly zip about, colliding with one another or with other objects. This is a complicated picture, but scientists simplified things by assuming that all the motions of the particles were random, that the only motion was translation (moving from place to place, as opposed to twisting, vibrating, and spinning), and that when particles collided, the collisions were elastic (perfectly bouncy, with no loss of energy).

How do you know which element is more reactive in the periodic table?

Generally, the elements become more reactive as you move down and to the left (in a diagonal line). As you move down, the outer electron shells are positioned further away from the positive nucleus, with the electrostatic force holding the element together growing weaker (due to increased distance).

Since gases move (translate), they will also do what?

mix in and blend with other gases in a container (diffusion)

Daily Uses of Gases: How do gases play a role in climate control?

Greenhouse effect-- accumulation of gases to trap the warmth from the sun. Too many = Bad

What are the charges of the PT?

Group 1: +1 Group 2: +2 Group 3: +3 Group 4: +/- 4 (depending on whether they accept or give away electrons) Group 5: -3 Group 6: -2 Group 7: -1 ... And group 8 has no charge because they neither will give nor accept electrons.

Explain why an element from group 6 generally reacts more easily with an element from group 2 or two elements from group 1 than with any others.

Group 6 with group 2: Group 6 has 6 valence electrons Group 6 with group 1: Group 1 has 1 valence electrons Group 2 has 2 valence electrons Group 6 needs two electrons. Group 2 offers those 2 electrons. Two elements from group 1 will also offer 2 electrons (since one element from group 1 offers 1 electron). This has to do with the completion of the outer shell.

Which group is more reactive: group 6 or group 7?

Group 7 because it is easier to gain one valence electron rather than two (group 6). Yahoo answer: group 6 or 7, or group 16 or 17? it makes a difference. if you compare the transition metals in groups 6 and 7, group 6 is more reactive. if you compare the oxygen family to the halogens (16 and 17) then the halogens are more reactive. why? the halogens need one electron to have an octet in their valence shell while the oxygen family need two electrons, it is easier to gain one than two, but of course there is more to it, electronegativity is highest with fluorine and next oxygen which shows how 17 is more reactive than 16, for example.

What are ideal gases?

The gas particles were assumed to neither attract nor repel one another. Gases that actually behave in this simplified way are called ideal

Which of the following will increase the number of collisions between gas molecules in a container? Increasing the size of the container. Letting some of the gas out of the container. Heating the gas. Bringing the container up a mountain where there is less atmospheric pressure.

Heating the gas. It is not the last choice because: if the container is closed, the atmospheric pressure doesn't affect the number of collisions. So in this case, it is closed because the answer doesn't include that. But, if the container were opened, then there is less pressure at altitude, so there will be fewer collisions.

Why is a triple bond much harder to break than a double bond or single bond?

Held on much harder because more bonds-- therefore the closer they are, the harder to break. It's like people.

Daily Uses of Gases: Balloons contain what gas?

Helium

How does the empty soda can inversion experiment work?

Here's the real scoop on the science of the imploding can. Before heating, the can is filled with water and air. By boiling the water, the water changes states from a liquid to a gas. This gas is called water vapor. The water vapor pushes the air that was originally inside the can out into the atmosphere. When the can is turned upside down and placed in the water, the mouth of the can forms an airtight seal against the surface of the water in the bowl. In just a split second, all of the water vapor that pushed the air out of the can and filled up the inside of the can turns into only a drop or two of liquid, which takes up much less space. This small amount of condensed water cannot exert much pressure on the inside walls of the can, and none of the outside air can get back into the can. The result is the pressure of the air pushing from the outside of the can is great enough to crush it. The sudden collapsing of an object toward its center is called an implosion. Nature wants things to be in a state of equilibrium or balance. To make the internal pressure of the can balance with the external pressure on the can, the can implodes. That's right, air pressure is powerful! One more thing . . . you probably noticed that the can was filled with water after it imploded. This is a great illustration of how air is pushing all around us. Specifically, the outside air pressure was pushing downward on the surface of the water. Since the air pressure inside the can was less than the pressure outside the can, water from the bowl was literally pushed up and into the can. This action is similar to what happens when you drink from a straw. Though we say we are "sucking" liquid up through the straw, we really aren't. To put it simply, science doesn't suck . . . it just pushes and pulls. Outside air pressure is pushing down on the surface of the liquid. When you reduce the pressure in your mouth (that sucking action) the outside pressure is greater than the pressure inside your mouth and the soda shoots up through the straw and into your mouth. The same thing is true with the can. The outside air pressure pushing downward on the surface of the water is greater than the force inside the can and the water gets pushed up into the can.

Txtbk Q pg. 107 #11. A 100-W bulb has a volume of 180 cm³ at STP. The bulb is lit and the heated glass dilates slightly, which increases the volume to 181.3 cm³. The internal pressure is 214.5 kPa. What is the temperature of the bulb in degrees Celsius?

Here, the 100 W is irrelevant. cm³ is just another unit for volume... Solve normally.

Most combustible gases are what?

Hydrocarbons

How can hydrogen gas be produced?

Hydrogen gas can be produced through electrolysis or from methane. Both methods consume large amounts of energy.

Dalton's Law: The pressure of each gas in a mixture is called what?

the partial pressure of that gas

Is O₂ an element or a compound?

It is an element since it's made up of one type of atom (oxygen).

Charles' Law: The temperature of a gas is measured in what?

Kelvin

In kinetic molecular theory, what is the temperature measured in? What is this called?

Kelvin degrees; absolute temperature

What are the units for pressure?

Kilopascal, kPa (the k and a are lower case, with P being upper-case), and the atmosphere, atm. The units could be either of them as long as they're consistent.

Ice floats in water. Based on the usual assumptions of kinetic theory, why is this weird?

Kinetic theory describes matter as moving from solid to liquid phase (melting) as you add energy to the sample. The added energy causes the particles to undergo greater motion, and to collide with other particles more energetically. Usually, this means that a liquid is less dense than a solid sample of the same material, because the greater motion of the liquid particles prevents close packing. Solid water (ice), on the other hand, is less dense than liquid water because of the unique geometry of water crystals. Because solid water is less dense than liquid water, ice floats in water.

Rank the four gases from slowest to fastest: CH₄, CO₂, Ar, Cl₂

Lightweight molecules will move faster than heavier molecules. Therefore, find the molar mass of each molecule: CH₄: M = 16 g/mol CO₂: M = 44 g/mol Ar: M = 40 g/mol Cl₂: M = 70 g/mol From slowest to fastest, the order is: Cl₂, CO₂, Ar, CH₄

Name a gas whose low reactivity is not only explained by the tendency to saturate its electron outer shell, but rather by another type of stability. Explain your answer.

Nitrogen gas, whose triple bond makes it unreactive

Textbook pg. 97 #16. A syringe with a maximum volume of 60.0 cm³ takes in a 14.5 cm³ sample of oxygen (O₂) gas at 24.3 °C. What maximum variation in temperature does the oxygen undergo before the piston is completely pushed out of the syringe?

Maximum variation means the difference in temperature... 1. Compile your data: V1 = 14.5 cm³ V2 = 60.0 cm³, since it is the maximum volume T1 = 24.3°C, must convert to kelvin...: 24.3 + 273K = 297.3 k 2. Use Charles' Law: V₁/T₁ = V₂/T₂ 14.5 cm³ / 297.3 k = 60.0 cm³/T₂ Cross multiply T₂ = 1230.21 k Maximum variation: 1230.21 k - 297.3 k = 932.91 k

The following formulas/constants will be given...: - General Gas Law: P1V1/(n1T1) = P2V2/(n2T2) - Ideal gas Law: PV = nRT - Dalton's 2 formulas: PT/nT = Pa/na = Pb/nb and Pt = Pa + Pb + Pc - R's constants - STP - SATP

Memorize the following... Molar volume ratio: STP: 22.4 L/mol SATP: 24.5 L/mol n = m/M n = C x V

Do particles lose kinetic energy by colliding with each other? Explain why or why not.

No because the collisions are perfectly elastic, meaning that they bounce back

How can gases be?

Monatomic, diatomic, or in compound

Daily Uses of Gases: Gases play an important role in many what?

Natural phenomena

Daily Uses of Gases: Gases also have a variety of technological applications. Give some examples.

Neon sign, food preservation and fire extinguishers.

Daily Uses of Gases: How does an airbag work?

Nitrogen gas inflates air bag, not hydrogen because it would explode. Nitrogen gas is very stable.

What is the name of group 3, 4, 5, and 6 in the periodic table?

Non-metals.

An amateur entomologist captures a particularly excellent ladybug specimen in a plastic jar. The internal volume of the jar is 0.5L, and the air within the jar is initially at 1 atm. The bug-lover is so excited by the catch that he squeezes the jar fervently in his sweaty palm, compressing it such that the final pressure within the jar is 1.25 atm. What is the final volume of the ladybug's prison?

Not going to solve, but just know that you keep your pressure values the same at 1 atm, no need to convert to kPa... but you can, using proportions, convert to kPa...

Chem Wkbk: Give an example of what would produce a change in moles.

Of course, the real universe can fight back by changing another variable. In the real universe, for example, tires spring leaks. In such a situation, gas particles escape the confines of the tire. This escape decreases the number of particles, n, within the tire. Cranky, tire-iron wielding motorists on the side of the road will attest that decreasing n decreases volume.

CONTINUE WITH THE ABOVE EXAMPLE

Know STP, SATP (the temperature, what it stands for, and pressure...)

Put sig figs on here, the review from last year in textbook (Q's got wrong) and whatever textbook Q's you did not put.

See Dad's math on chemistry Q's in binder about the inversely proportional part.

Simple gas laws won't be given for exams...

How to tell if they mean the actual element of hydrogen or hydrogen gas if they just tell you hydrogen?

Ok, ask teacher. They usually mean hydrogen gas. When they mean an element, they're referring to atoms in a chemical.

Describe the math behind Charles' Law.

On a graph, it's a directly proportional graph, meaning it's a positive-sloped line passing through (0,0). V (volume) is on the y-axis and T (temperature) is in kelvin and is on the x-axis. Ask Dad why. And the title of the graph is V vs. T (Ask Dad why). There is no y-intercept in this graph. Must be in the first quadrant because it would be impossible to have negative values. The slope is always constant (the same) for that line. Let's say we take two points: (T₁,V₁) and (T₂, V₂) and also (0,0) Calculate the slope for both: a = V2 - 0 / T2 - 0 = k or a = V1 - 0 / T1 - 0) = k So generally V / T = k *the "k" is the same number for both!

Explain the following phenomenon using the particle model of matter: Milk spreads throughout a cup of coffee.

Particles are always moving

Chem Wkbk: The volume of a whoopee cushion is 0.450L at 27.0°C and 105 kPa. Danny has placed one such practical joke device on the chair of his unsuspecting Aunt Bertha. Unbeknownst to Danny, this particular whoopee cushion suffers from a construction defect that sometimes blocks normal outgassing and ruins the flatulence effect. So, even when the cushion receives the full force of Aunt Bertha's ample behind, the blockage prevents deflation. The cushion sustains the pressure exerted by Bertha, so that the internal pressure becomes 200 kPa. As she sits on the cushion, Bertha warms its contents a full 10.0°C. At last, and to Danny's profound satisfaction, the cushion explodes. What volume of air does it expel?

P1 = 105 kPa V1 = 0.450 L T1 = 300 K P2 = 200 kPa V2 = ? T2 = 283 K Cancel out n from the formula, and isolate for V, should get V2 = 0.244 L Despite the fact that the final temperature is higher than the initial temperature, the final volume is much smaller than the initial volume (that's because volume and temperature are directly proportional to each other...). In effect, 10 trifling degrees are no match for the pressure exerted by Bertha's posterior.

What is Dalton's Law of partial pressure? What do its components represent?

PT / nT = PA/nA = PB/nB = ... *The subscripts following P and n should be written as subscripts... Where: PT = total pressure PA and PB = partial pressures of gases A and B within the mixture nT = total # of moles in gas mixture nA and nB = # of moles of each gas in the mixture

Chem Wkbk: A 0.80L container holds 10 mol of helium. The temperature of the container is 10°C. What's the internal pressure of the container in atm? How many times from normal atmospheric pressure is it?

PV = nRT P x 0.8 L = 10 mol x 0.082 atmL/molK x 283 K (You would just simply use R = 0.082 atmL/molK) P = 290.075 atm In scientifc notation: To format your number in this way, we'll divide the 290.075 by 10, 2 time(s), making it a 2.90075. We do this, because each division by 10 moves the decimal point to the left one digit. But in order to keep our number the same number, we must have a × 102 next to the 2.90075. So, the final answer is 2.90075 × 102 290.075 atm divided by 1.1 atm = 263.7 times the normal atmospheric pressure

By analyzing the general gas law, we can notice that what?

PV ∝ nT or in other words, numerator ∝ denominator

What is the formula for the ideal gas law?

PV=nRT

Name the physical roles that gases can play. Is this harmful or beneficial for the environment?

Physical roles involve a physical change; a change of phase. So NOT combustion (that would be a chemical change). The physical roles are: - The extinguisher because it's "smothering" (physical) the fire - Preserving food (nitrogen) because nitrogen isn't reactive. These are all useful for the environment.

What does ozone do?

Protects us from UV rays.

Chem Wkbk: How does increasing the number of particles also increase the pressure proportionally?

Ptotal = P1 + P2 + P3 + . . . + Pn This relationship makes sense if you think about pressure in terms of kinetic molecular theory. Adding a gaseous sample into a volume that already contains other gases increases the number of particles in that volume. Because pressure depends on the number of particles colliding with the container walls, increasing the number of particles increases the pressure proportionally.

Gay-Lussac's Law

P₁ / T₁ = P₂ / T₂ *Temperature must be in Kelvin

What is the formula for the General Gas Law?

P₁V₁/(n₁T₁) = P₂V₂/(n₂T₂) MUST PUT BRACKETS ON DENOMINATOR!... Also, when things are constant, just elimate them from the formula....

What are some examples of hydrocarbons?

Remember that hydrocarbons contain carbon and hydrogen. Here are some examples: glucose: C₆H₁₂O₆; ethane C₂H₆

Write a balanced equation for the combustion of propane in air.

Remember, in a combustion reaction, there is an oxidizer and the fuel. In this case, the fuel is propane. The oxidizer is simply oxygen gas, O₂. Additionally, the products of a combustion reaction are carbon dioxide and water vapor. The molecular formula for propane is C₃H₈. O₂ + C₃H₈ → CO₂ + H₂O Balancing-- Reactants: 3 C 8 H 2 O... x5 = 10 O Products: 1 C... x3 = 3 C 2 H... x4 = 8 H 10 O TRICK: always balance your oxygens last. Hence we have: 5O₂ (g) + C₃H₈ → 3CO₂ (g) + 4H₂O (g) *Always put the states/phases. In this case, they're all gases, represented by: (g) *Water vapor (H₂O) is water in its gaseous state/phase.

You have the following variables: v2 = unknown velocity v1 = 0.178 times that of the unknown velocity M2 = 2 g/mol M1 = ?

Rewrite variables as such... v2 = x v1 = 0.178x M2 = 2 g/mol M1 = y Use Graham's Law: v2/v1 = √M₂/M 0.178x/x = √2/M₁ The x's will cancel out... 0.178/1 = √2/M₁ Solve normally... 0.178² = 2/M1 0.031684 = 2/M1 M1 = 63.12 g/mol

Categorize the phases of matter according to the degree of disorder of the particles that compose the matter. Start with the phase with the least disorder.

Solid, liquid, gas In a solid, the particles are uniformly placed. In a gas, they're a bit all over the place and very far from one another. In a liquid, it's a little bit of both.

Particles of matter attract or repel each other, and the force that attracts or repels them from each other varies depending on the distance that separates them. In which state will the force of attraction be stronger? Weaker?

Solids will have the strongest force of attraction. Liquids will have a strong force of attraction. Gases will have a negligible force of attraction.

Molar Concentration info (relevant for solving # of moles for stoichiometry and gas laws...)

Symbolized by placing the chemical formula for the measured substance inside square brackets: [NaCl] = 0.5 mol, for example. The formula is: C = n/V, where C is measured in mol/L, and V is obviously measured in L. It is represented as, for example: 0.1 mol/L or 0.1 M (same thing) Example: Determine the molar concentration of a 400 mL solution made using 3.01x10²⁴ molecules of NaCl. C = n/v n = 6.02 x 10²³/1 mol = 3.01 x 10²⁴/x mol x = 5 moles C = n/v = 5 mol/0.4 L = 12.5 mol/L or 12.5 M.

Represent Gay-Lussac's Law mathematically.

T ∝ P. Ask Dad if it can be P ∝ T. Answer: It can. *T must be in Kelvin P is on the y-axis and T is on the x-axis (Ask Dad why). Again, it's a straight line that passes through (0,0). X and y are not necessarily the same value because the scale on the axes can be different. If one doubles, the other doubles as well. If we take two points: (0,0) with (T1, P1) or (T2, P2) a = P2 - 0 / T2 - 0 = k a = P1 - 0 / T1 - 0 = k *Pick your points in order (x1, y1, x2, y2) *k is the same value. The equation for the graph can be represented with: P / T = a (like in the formula, but in the formula "a" is not there, but they are equal to each other because of the same k value):

An unknown gas is collected in a 250 mL container which is then sealed. Using electronic instruments, the gas inside the container is found to exert a pressure of 135.5 kPa at 15°C. What pressure would the gas exert if the temperature in kelvin (K) is doubled?

The constant is volume: 250 mL because they do not describe a change in volume. P₁ = 135.5 kPa T₁ = 15°C + 273 k = 288 K T₂, temperature is doubled: 288 K x 2 = 576 K P₂ = ? Use Gay-Lussac's law to solve for P₂.

What relationship does Charles' Law explore? Explain.

The directly proportional relationship between volume and absolute temperature. As one increases, the other increases as well, and vice-versa.

How does the electron configuration affect chemical reactivity?

The elements having a completely filled outermost orbit (or shell) will be chemically inert (non- reactive). For example, the outermost shell in the case of helium (He), neon (Ne) and argon (Ar) are completely filled as shown below. As a result, helium, neon, and argon are chemically inactive (or inert). These elements do not form compounds with other elements. Because of this chemical inactivity, these gases are called as noble gases (earlier these were called inert gases). The elements containing only one or seven electrons in their outermost shell show greater chemical reactivity, i.e., such elements react very fast with other elements. For examples, sodium and chlorine having the follows electronic configurations are highly reactive. Sodium 2, 8, 1 ---- Here, the outermost shell has been one one electron: one more than the completely filled shell. Chlorine 2, 8, 7 ----- Here, the outermost shell has seven electrons: one less than that required to fill the shell completely.

A cup of water is put into a freezer and cools to the solid phase within an hour. The water remains at that temperature for six months. After six months, the cup is retrieved from the freezer. The cup is empty. What happened?

The frozen water sublimed, moving directly from a solid to a gaseous state. This process occurs slowly at the temperatures and pressures found within normal household freezers, but does occur.

Lab demo: The heat from the hot plate transformed its heat energy to the water inside the can, warming the water which turned into air (water vapor) and causing the air to be less dense. How did this affect what happened to the can?

The heat caused the metal of the can to be softer and more malleable since the metal was conducting heat.

Lab demo: What effect did the heat from the hot plate have on the contents of the can?

The heat from the hot plate transformed its heat energy to the water inside the can, warming the water which turned into air (water vapor) and causing the air to be less dense. Less dense = warmer

Which of the following is not a factor in the chemical reactivity of a gas? Strength of the bonds between its atoms The molecule's ability to combust. Force of attraction between the valence electrons and the nucleus of its atoms. Electron configuration of its atoms.

The molecule's ability to combust. Electron configuration: chemical reactivity is determined by the outer electrons and the valence electrons. When substances react chemically, it's mainly because of the electrons trying to configure themselves by sharing electrons to reach the lowest possible energy state. That's why atoms combine chemically. Entropy: things will want to go to the lowest energy state because it takes energy to have the reverse effect. It is trapped in the lowest energy state until you add energy. Force of attraction: brings the atoms together, what makes them stick together is the electrons sharing orbitals. The force of repulsion between the protons can be minimized by placing the pair of electrons between the two nuclei. The distance between the electron on one atom and the nucleus of the other is now smaller than the distance between the two nuclei. As a result, the force of attraction between each electron and the nucleus of the other atom is larger than the force of repulsion between the two nuclei, as long as the nuclei are not brought too close together. So basically, when the force of attraction is strong, they stick together and therefore this results in a lower reactivity. Likewise, when the force of attraction is weak, it is more reactive.

What is the kinetic energy like in a liquid and gas?

The particles within a liquid are much closer together than those in a gas. As a result, applying pressure to a liquid does very little to change the volume. The particles still have an appreciable amount of kinetic energy associated with them, so they may undergo various kinds of twisting, stretching, and vibrating motions. In addition, the particles can slide past one another (translate) fairly easily, so liquids are fluid, though less fluid than gases. Fluid matter assumes the shape of anything that contains it. The state of matter with the least amount of kinetic energy is the solid. In a solid, the particles are packed together quite tightly and undergo almost no translation. Therefore, solids are not fluid. Matter in the solid state may still vibrate in place or undergo other low-energy types of motion, however, depending on its temperature (in other words, on its kinetic energy).

Which bond is easier to break? The single bond in a fluorine molecule, F₂, or the triple bond in the nitrogen molecule, N₂? Explain.

The single bond; takes less energy to break

Chem Wkbk: A chemist adds solid zinc powder to a solution of hydrochloric acid to initiate the following reaction: Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) The chemist inverts a test tube and immerses the open mouth into the reaction beaker to collect the hydrogen gas that bubbles up from the solution. The reaction proceeds to equilibrium. At the end of the experiment, the water levels within the tube and outside the tube are equal. The pressure in the lab is 101.3 kPa, and the temperature of all components is 298K. The vapor pressure of water at 298K is 3.17 kPa. What is the partial pressure of dihydrogen gas trapped in the tube?

The temperature is constant. The total pressure includes the partial pressure contributions from dihydrogen and from water vapor. Set up an equation using Dalton's Law: Ptotal = P(H2) + P(H2O) Rearrange the equation to solve for P(H2) and substitute in the known values to solve: P(H2) = 101.3 kPa - 3.17 kPa = 98.1 kPa Ask Dad: what about the other components of the chemical equation? How do I know which elements/compounds to use?

How does the temperature and pressure affect the states?

The temperatures and pressures at which different types of matter switch between states depend on the unique properties of the atoms or molecules within that matter. Typically, particles that are very attracted to one another and have easily stackable shapes tend toward condensed states. Particles with no mutual attraction (or that have mutual repulsion) and with not so easily stackable shapes tend toward the gaseous state. Think of a football game between fiercely rival schools. When fans of either school sit in their own section of the stands, the crowd is orderly, sitting nicely in rows. Put rival fans into the same section of the stands, however, and they'll repel each other with great energy

What phenomenon can propane, oxygen gas, and carbon dioxide be associated with? Specify the role that each gas plays in this phenomenon.

They can all be associated with combustion. Propane acts as a fuel, oxygen as the oxidizing agent, and carbon dioxide as the product of combustion. They are NOT associated with the greenhouse effect because propane is NOT a greenhouse gas.

The rate of effusion of an unknown gas is estimated at 43.0 mL/min. Under the same conditions, the rate of effusion of pure carbon dioxide is 32.0 mL/min. What is the molar mass of the unknown gas? Before you calculate anything, which gas is going to be faster and what does this imply?

The unknown gas is moving faster,therefore the molar mass is going to be lighter because of the inversely proportional relationship between velocity and molar mass. Since we're talking about rates, let's use the Graham's Law: v₁/v₂ = √M₂/M₁ Find the molar masses first 43.0 / 32.0 = √44 g/mol /M₁ 1.34375² = 44/M1 (divide the left side, then square the left side to get rid of the square root) 1.806 = 46/M1 M1 = 25.47 g/mol

How is the ideal gas law different from the other gas laws?

There are no initial/final conditions. Whatever the problem describes, it is happening at one time.

Avogadro's Law: Two cylinders are used to store different gas samples. If each cylinder is at 273 K and 100 kPa, which cylinder is larger? Cylinder A contains 16 grams of oxygen gas, O₂. Cylinder B contains 16 g of neon gas, Ne.

This is a theory question. Notice how temperature and pressure are constants here, therefore it is Avogadro's Law because these variables are excluded in the formula. We know that volume is directly proportional to the number of moles. So all you need to do is find the molar mass of each, find the number of moles, and the one with the greater number of moles is the one with the greater volume since volume and the number of moles are directly proportional. Explain this on a test... (that they are proportional). Molar of oxygen gas: 32 g/mol, n = 0.5 mol M of Neon: 20 g/mol, n = 0.8 mol Neon gas has the greater volume.

Quiz Q: True or false? Temperature has no effect on the velocity of gas molecules.

This is false because temperature DOES have an effect on the kinetic energy; which will affect the velocity because Ek = 1/2mv². Notice how the kinetic energy and the velocity are in the same formula. Temperature has an effect on velocity... the speed is dependent on mass: heavier molecules move slower...

General Gas Law: A 100 g sample of carbon dioxide, CO₂, is placed into a 1.5 L balloon at 20°C and 100 kPa. The balloon is then brought outside at a temperature of 27°C and a pressure of 1.1 atm. If 10 g of the carbon dioxide has escaped from the balloon, what is its new volume?

Trick: List all your values as such: P1: 100 kPa V1: 1.5 L n1: m/M = 2.27 mol T1: 20 + 273 = 293 K P2: 101.3 kPa x 1.1 atm = 111.3 kPa V2: Unknown n2: n/m = 2.05 mol T2: 27 + 273 = 300 K 1. Find the number of moles for carbon dioxide using n = m/M. 2. "10 g escaped" : 100 g - 10 g = 90 g..., so calculate the number of moles (n2) using 90 g. 3. Plug values into formula and isolate V2. Fairly obvious on how to solve.

Balance: Fe₂O₃ + CO --> Fe + CO₂

Trick: balance the oxygens last 2 Fe₂O₃ + 6 CO --> 4 Fe + 6 CO₂ Just reduce the coefficients by dividing by two... Fe₂O₃ + 3 CO --> 2 Fe + 3 CO₂

Txtbk Example: What is the molar mass of a sample of an unknown gas, if, at a temperature of 0°C and under a pressure of 102 kPa, a volume of 2.30 L of the gas weighs 4.23 g?

Use PV = nRT with your variables to get the number of moles, then use M = m/n to get the molar mass.

2.0 moles of Neon (Ne), 3.0 moles of Argon (Ar), and 4.0 moles of Helium (He) are in a cylinder with a total pressure of 325 mm Hg. What are the partial pressures of the Ne, Ar, and He?

Use Pt/nt = Pa/na 325 mmHg/9 mol = Pa/2 mol Pa = 72 mmHg for Ne Do this for the rest...

What quantity of methane (CH₄) gas is found in a sample with a volume of 500 mL at 35°C and 210 kPa?

V = 500 mL, BUT it has to be in L because R = kPaL/molK (so the units have to be consistent...) So use KLM trick to get to 0.5 L... As you go right, you multiply by 1000 at each step... As you move left, you divide by 1000 at each step... T = 308 K P = 210 kPa Then solve for the number of moles normally, should get 0.04 mol... Make sure units always match up with constant...

How is the relationship between volume and temperature in Charles' Law represented?

V ∝ T or T ∝ V

Avogadro's Law: Represent the directly proportional part.

V ∝ n

Prove that the pressure doubles when the volume is halved.

Use this equation: P = 1/V, P = 1 / 1/2, P = 2

Prove that the pressure is halved when the volume is doubled.

Use this equation: P = 1/V, P = 1/2

How can we figure out if a molecule has a single, double or triple bond?

Using a Lewis Dot diagram.

If atoms are infinitely small, then how do we know they're there?

Using an atomic force microscope, people have actually imaged atoms. There is a large body of knowledge backed up by experimental data that atoms exist. However, atoms are made up of smaller particles and as far as we know, those smaller particles may be made up of even smaller particles. The cutting edge of particle physics is still under research and it may be decades before there is consensus over what things look like below the atom.

Will carbon dioxide and helium have the same kinetic energy? What has to be the same in order for them to have the same kinetic energy?

While they both have a different molar mass, velocity is what makes them the same. The velocity won't be the same number either, but it according to how heavy/lightweight the molecules are, will move at their own velocity but will ultimately equal to the same average kinetic energy. They bounce off of each other and they transfer Ek to each other. Energy never gets lost, only converted or transferred (like in this case).

P. 110 #3) A barbecue burns 1.5 L of propane (C₃H₈) gas. This combustion is expressed by the following equation: C₃H₈ (g) + 5O₂ (g) → 3CO₂ (g) + 4H₂O (g) a) What is the volume of carbon dioxide gas produced? b) What is the volume of oxygen (O₂) used?

You could only do this type of ratio if ALL of the components are gases, expressed as (g) in the chemical equation...(the ratio is like as if you had moles instead of liters): a) 1 L C₃H₈ / 1.5 L C₃H₈ = 3 L CO₂ / x x = 4.5 L of CO₂ b) 3 L CO₂/4.5 L Co₂ = 5 L O₂/x x = 7.5 L of O₂ OR you could do... (many ways of doing the ratio, so long as it is a ratio between the balanced chemical equation and from the word problem...) 1 L C₃H₈/1.5 L = 5 L O₂/x x = 7.5 L of O₂

Textbook pg. 51 #5. d. What function does O₂ serve?

a constituent of the atmosphere essential for respiration

The distance between gas particles is very large. What does this allow?

a given quantity of a gas can be compressed into a smaller volume (compressibility)

What is stoichiometry?

a method of problem-solving that makes use of the law of conservation of matter

Molar volume: Under certain conditions (meaning STP, SATP), the volume of any gas could be simply calculated through what?

a molar volume ratio.

Since gases translate, what can they do?

collide with other particles or the walls of their container.

What are used in the combustion reaction to produce energy?

combustible gases such as hydrocarbons and hydrogen (H₂)

Lightweight molecules move faster or slower than heavier molecules?

faster

As seen in kinetic molecular theory, gases have the ability to move in what way? Give an example.

in all ways: vibration, rotation and translation. They can move randomly in any direction. For example, they can move to a high pressure environment to a low pressure environment.

What are oxidizers?

substances that reduce the overall charge of a reactant atom, or group of atoms, during the formation of the products

Daily Uses of Gases: Gases also have a variety of what?

technological application

What does Dalton's Law state?

that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each of the component gases

What does Graham's Law state?

that when temperature and pressure are constant (notice how these variables are not in the formula), the rate at which a gas moves (diffusion or effusion) is inversely proportional to the square root of the molar masses. In other words, if you have a heavier molecule (greater molar mass), it'll have a slower velocity (smaller velocity). If you have a lighter molecule (smaller molar mass), it'll have a faster velocity (greater velocity).

Explain Fluorine with Coulomb's Law.

the 7 valence electrons are closer to the electron shell, so the electron shell has more grabbing abilities, pull is stronger, so it's most reactive. The protons attract the electrons to the atoms, while the electron shells actually go and grab the electrons.

How many types of gases are involved in a combustion reaction? What are they?

the combustible gas (fuel) and the oxidizer

Stoichiometry: What is used in stoichiometric calculations?

the molar ratio in a balanced equation

What will happen to the pressure in a container as temperature decreases?

the number of collisions decrease since the kinetic energy of the molecules is slower, therefore the pressure will decrease, too

What will happen to the pressure in a container as temperature increases?

the number of collisions increase since the kinetic energy of the molecules is faster, therefore the pressure will increase, too

What does photosynthesis also enable?

the oxidation of metals and some of its alloys (since photosynthesis releases oxygen)

Electrons have a negative charge, so who grabs the electrons?

the protons

How can we use nitrogen to our advantage?

to make proteins for living organisms

When is stoichiometry of gases used?

to determine the quantity of a reactant needed in a reaction and to predict the quantity of the product obtained following a reaction in which at least one of the components is gaseous

What does chemical reactivity make possible?

to distinguish one gas from another or to classify gases in a group based on similar chemical reactivity

How can we use atmospheric pressure to our advantage?

to fill up a space and apply lots of pressure to it, can also create a vacuum (removing gases from that area)

Gases can be diatomic. What does that mean? Give examples.

two atoms; I₂, H₂, N₂... two of the same atom

What type(s) of motion do liquid molecules undergo?

vibration and rotation. Rotation can occur on any axis; x, y, z

What type(s) of motion do gases undergo?

vibration, translation, and rotation

Daily Uses of Gases: How does anesthesia work?

you inhale anesthesia gas

What's an example of effusion?

when balloons deflate because of tiny openings in balloon.

What will the oxidizer do during an oxidation reaction?

will accept electrons from the substance undergoing oxidation. Therefore, the charge will become more negative.

Charles' Law: If the volume is doubled, what will happen to the temperature in Kelvin?

will also double (IN KELVIN...)

What is the general equation for the inverse function?

y = a / x OR xy = a (same thing). It's like saying y = 1 / x, but you could scale x or y by a factor of "a"; meaning that if you had y = 2/x for example, the inverse function line would be stretched upwards compared to y = 1/x. If you had y=1/2x, then the line would curve lower. There is no "b" because there is no y-intercept.

Can we use stoichiometry if the components are not gaseous?

yES

Symbol for density

ρ (VERY IMPORTANT...)

See all study sets

[CHEMISTRY]: Gases: Chemical Properties of Gases, [CHEMISTRY]: Chapter 2: Gases-- Kinetic Molecular Theory (KMT)

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