Chem 14 gases
How many moles of xenon gas are necessary to exert a 0.64atm pressure in an 8.5L container at 300.0K?
0.22 moles
Nitrogen dioxide (NO2) is a pollutant that is primarily removed from the atmosphere by reaction with hydroxyl radicals (OH) to form nitric acid (HNO3). NO2(g)+OH(g)⟶HNO3(aq) How many grams of nitric acid are produced from this reaction if it reduces the partial pressure of NO2 from a 1.3×10^9L volume of air over a city by 4.5×10^−8atm when the temperature is 10∘C? Your answer should have two significant figures.
160g
What is the most likely identity of a gas with a molar mass of 16.2gmol?
CH4
Which is a correct way of stating Charles's law? V=kT VT=k V1 / T1=V2 / T2 all of the above
all of the above
For an ideal gas, volume and temperature are __________ proportional.
directly
Standard temp and pressure (STP-ideal gas)
one mole 22.4 liters
Avogadro's Law
states that increasing the number of gaseous molecules will require a proportional increase in the container volume in order to maintain a constant pressure and temperature. The KMT is describing Avogadro's law. As the number of gas particles increases, the number of collisions between the walls of the container must increase, causing an increase in gas pressure. This increase in pressure will cause an increase in volume to decrease the collisions. So the volume of the gas is proportional to the number of gas particles.
mole fraction Pa = Xa p
substance is the % of the total mixture repented by that substance is a unitless quantity, so do not include units in your response.
A sample of a gas has a volume of 30.0 mL at a pressure of 6.50 psi. Determine the volume of the gas in milliliters at a pressure of 11.0 psi. Your answer should have three significant figures (round your answer to one decimal place).
(30.0 x 6.50) / 11.0 = 17.7
A 650 mL sample of neon gas exerts a pressure of 0.125 atm. If compressed until the pressure is 0.600 atm, what will be the final volume of the sample in milliliters? 3sf
(650mL x 0.125atm) / 0.600atm = 135mL
first phone picture
(a) When gas temperature increases, gas pressure increases due to increased force and frequency of molecular collisions. (b) When volume decreases, gas pressure increases due to increased frequency of molecular collisions. (c) When the amount of gas increases at a constant pressure, volume increases to maintain a constant number of collisions per unit wall area.
Which of the following can be explained by the kinetic molecular theory (KMT)? Select all that apply.
-Increasing rates of collisions of gas particles with their container as temperature increases translates to a higher pressure within that container. -Lowering the temperature of gas molecules decreases their average kinetic energy. -Increasingly energetic collisions between gas particles and walls of the chamber lead to increasing pressure with increasing temperature.
If the temperature inside a balloon decreases, the volume will __________________. (Select all that apply)
-decrease. -depend on the magnitude of the change in temperature.
A student wants to crush a can and needs to double the pressure they are applying to the can. Which action can they take to accomplish this?
-double the force applied and keep the area the same -keep the force the same and decrease the area by 12
In a mixture of 1.75 moles of gas, 0.75 moles are nitrogen molecules. What is the mole fraction of nitrogen in this mixture?
.75/1.75 = 0.43
A mixture with H2 and He exerts a total pressure of 0.48 atm. If there is 1.0 g of H2 and 1.0 g of He in the mixture, what is the partial pressure of the helium gas?
0.161
A sample of hydrogen gas at 0.35 bar and 500 cm3 is allowed to expand to 750 cm3. What is the final pressure of the system in bar? Your answer should have two significant figures (round your answer to two decimal places).
0.23
A mixture with H2 and He exerts a total pressure of 0.48 atm. If there is 1.0 g of H2 and 1.0 g of He in the mixture, what is the partial pressure (in atmospheres) of hydrogen? -round to nearest 100th
0.391
A balloon containing 0.10 moles of helium gas has a volume of 1.25 liters. If the volume is increased to 2.75 liters with no change in pressure or temperature, how many grams of helium have been added?
0.48 grams
The kinetic molecular theory (KMT) is a simple microscopic model that effectively explains the gas laws.
1- Gases are composed of molecules that are in constant motion, traveling in straight lines and changing direction only when they collide with other molecules or with the walls of a container. 2- The molecules composing the gas are negligibly small compared to the distances between them. 3 - The pressure exerted by a gas in a container results from collisions between the gas molecules and the container walls. 4- Gas molecules exert no attractive or repulsive forces on each other or the container walls; therefore, their collisions are elastic (do not involve a loss of energy). 5 -The average kinetic energy of the gas molecules is proportional to the absolute temperature (the temperature in units of kelvin, K) of the gas.
A balloon has 1.00 L gas at sea level (1.00 atm). If the balloon is taken to a point with air pressure of 0.850 atm, what will the new volume be in liters? Your answer should have three significant figures (round your answer to two decimal places). Do not include units in your response.
1.18
how many molecules of hydrogen are in 67.2L of H2 at STP?Use NA=6.022×10^23mol−1 for Avogadro's number.Your answer should have three significant figures. (Round to two decimal places in scientific notation.)
1.81 x 10^24
Air pressure at sea level is equal to
14.7 psi
A piston containing 0.120moles of methane gas, CH4, has a volume of 2.12liters. If methane is added until the volume is increased to 3.12liters with no change in pressure or temperature, how many grams are in the piston? Your answer should have three significant figures.
2.83
What is the molar mass of 2.45 L of an unknown gas with a mass of 3.87 g at 325 K and 2.00 atm?
21.1
How many moles of gas are in 30.0 L of a contained tube with a temperature of 300.K and pressure at 200. atm? Use R=0.08206L atmmol K for the gas constant.
244
A sample of gas has a volume of 15.0 mL at a pressure of 13.0 psi. Determine the pressure of the gas at a volume of 7.5 mL.
26 psi
A sample of gas isolated from unrefined petroleum contains 9.00 mol CH4,0.890 mol C2H6, and 0.110 mol C3H8 at a total pressure of 307.2 kPa. What is the partial pressure of CH4?
276
N2(g)+3H2(g)⟶2NH3(g) If 4.5×10^4L of hydrogen is consumed, how many liters of ammonia are produced (at the same temperature and pressure)?
3.0 x 10^4 L
Sulphuric acid decomposes into H2O and SO3. H2SO4(l)⟶H2O(g)+SO3(g) If 10.0 g of sulphuric acid is completely decomposed in a closed container with a total volume of 3.00 L and no air at 350∘C, what will the total pressure in the container be in atmospheres? Assume the volume of the liquid is negligible.
3.5
If a balloon at 25∘C with 2.3 L of volume is expanded to 40.0 L, what will the new Celsius temperature be?
4,900
Electrolysis of water is a process that uses electrical current to separate water into its component elements. 2H2O(l)⟶2H2(g)+O2(g) If 10.0g of water is completely electrolyzed in a closed container with a total volume of 5.00L and no air at 25∘C, what will be the partial pressures of the products and the total pressure in the container? Assume the volume of the liquid is negligible.
4.07 atm
All of the following exert a force of 250 lb. Which of the following would exert the most pressure, given their surface areas?
5 in^2 water heater P= 250 lb / 5 in^2 =50 lb in^2
What pressure (in torr) of carbon dioxide gas can be produced by the combustion of 1.00g of benzene (C6H6) in a closed, 25.0L container at a temperature of 15∘C? 2C6H6(l)+15O2(g)⟶12CO2(g)+6H2O(l)
55.2
Convert 735 torr to mmHg.
735 mmHg
Air pressure at sea level is equal to: (select all that apply)
760 torr 1 atmosphere 101,325 pascals
The ideal gas law displays the relationship in which of the following?
Amontons's law Charles's law Boyle's law Avogadro's law
Which of the following states that the pressure of a given amount of gas is directly proportional to its temperature on the Kelvin scale when the volume is held constant?
Amontons's or Gay-Lussac's law
Avogadro's Law.
At constant pressure and temperature, the frequency and force of molecule-wall collisions are constant. Under such conditions, increasing the number of gaseous molecules will require a proportional increase in the container volume in order to maintain a constant pressure and temperature. (Figure 1). Mathematically, V∝n at constant T and P.
According to KMT, at constant pressure and temperature, the frequency and force of molecule wall collisions are constant. So increasing the number of gaseous molecules will require a proportional increase in the container volume in order to yield a decrease in the number of collisions per unit area to make up for the increased frequency of collisions. What gas law is KMT explaining?
Avogadro's Law
Alison observes that when she injects additional gas molecules into a container of gas, the number of collisions in the container (and the pressure inside) increases. She then increases the volume of the container just enough to restore it to its original pressure. Which of the following laws best describes what Alison observed?
Avogadro's Law
Dalton's Law.
Because of the large distances between them, the molecules of one gas in a mixture bombard the container walls with the same frequency whether other gases are present or not, and the total pressure of a gas mixture equals the sum of the (partial) pressures of the individual gases. Mathematically, Ptotal=PA+PB+PC+...=∑iPi.
The relationship between pressure and volume is inversely proportional.
Boyle's law: The volume of a given amount of gas held at constant temperature is inversely proportional to the pressure under which it is measured.
A sample of nitrogen gas, (N2), occupies 45.0 mL at 27.00∘C and 80.0 kPa. What will be the pressure if the gas is cooled to −73.00∘C at constant volume? Use −273.15∘C for absolute zero.
Convert C to K (80kpa x 200.15 k ) / 300.15 k = 53.3 kpa
Boyle's Law.
If the gas volume is decreased, the container wall area decreases and the molecule-wall collision frequency increases, both of which increase the pressure exerted by the gas (Figure 1). Mathematically, P∝1V at constant T and n.
Amonton's Law.
If the temperature is increased, the average speed and kinetic energy of the gas molecules increase. If the volume is held constant, the increased speed of the gas molecules results in more frequent and more forceful collisions with the walls of the container, therefore increasing the pressure (Figure 1). Mathematically, P∝T at constant V and n.
Charles's Law.
If the temperature of a gas is increased, a constant pressure may be maintained only if the volume occupied by the gas increases. This will result in greater average distances traveled by the molecules to reach the container walls as well as increased wall surface area. Mathematically, V∝T at constant P and n.
volume and temp are related
If we have gas in a balloon and we heat it up, the particles will move more quickly. In order to keep pressure constant, or hit the sides with the same frequency, the volume will have to expand. The balloon volume expands for the balloon that has the heat source. The pressure gauge begins to fall to the left, indicating a lower pressure. - This means that volume and temperature are directly proportional.
Decreasing the volume of a contained gas will increase its pressure, and increasing its volume will decrease its pressure as long as the temperature is held constant
In fact, if the volume increases by a certain factor, the pressure decreases by the same factor and vice versa
Which is a correct way of stating Boyle's law?
P=k×1V, where k is a constant. PV=k, where k is a constant. P1V1=P2V2, where the indices 1 and 2 corresponds to different states of the same gas sample.
Ideal Gas Law
PV=nRT R is ideal gas constant = 0.08206
The KMT addresses the origin of gas pressure, the relationship between the temperature and kinetic energy of a gas, and the attraction among gas particles:
The increasing kinetic energy associated with increasing temperature means higher average speeds, so both more frequent and more energetic collisions with the walls, leading to increasing pressure.
Which plot will give a straight line?
V vs. 1P Volume and pressure are inversely related, so only the reciprocal of the pressure against volume results in a linear plot.
Avogadro's law: For a confined gas, the volume (V) and number of moles (n) are directly proportional if the pressure and temperature both remain constant. In equation form, this is written as:
V∝n or V=k×n or V1/n1=V2/n2.
If one doubles, the other must double. This is expressed in Charles's law.
When we do calculations with temperature, we must always use an absolute temperature scale, called the Kelvin scale.
For which gas will one mole occupy 22.4 liters at standard temperature and pressure? helium oxygen nitrogen all of the above
all of the above Any ideal gas will have the same molar volume, 22.4 liters at STP.
Pressure is inversely proportional to which of the following, assuming all other variables are constant?
area Pressure is inversely proportional to area for a constant forces because pressure is the force applied per area: P=FA
According to kinetic molecular theory, pressure exerted by a gas is due to __________. collisions between the gas molecules and the container walls the gas molecules being negligibly small inelastic collisions between gas molecules all of the above
collisions between the gas molecules and the container walls -When gas particles hit the sides of a container, they exert pressure on that container.
What method of walking would apply the least amount of pressure on a surface?
crawling on all fours
If the gas inside a rigid container is cooled, the pressure __________.
decreases
According to Boyle's Law, if the pressure in a container filled with air is quadrupled, we know that the volume must be __________.
divided by four
Calculating the molar mass of a gas can be useful because it will allow us to:
identify the gas Using the molar mass, we can usually determine the precise identity of the gas, as most common gases have a molar mass that is not shared with other gases.
Pressure and volume of an ideal gas are __________.
inversely proportional As volume decreases, the pressure will increase if temperature is kept constant, according to Boyle's law.
Molar mass (M) is equal to the following, where m is the mass in grams and n is the amount in moles:
m / n
What relates the partial pressure of a gas to the total pressure of a gas mixture?
mole fraction
Under conditions of constant temperature and amount of substance, a plot of pressure vs. volume for an ideal gas will result in __________. a line a parabola a logarithmic function none of the above
none of the above This plot will give a hyperbolic relationship because there is an inverse relationship between the pressure and the volume of an ideal gas under conditions of constant temperature and constant amount of substance (constant number of moles, n).
he P-T relationship for gases is known as either Amontons's law or Gay-Lussac's law
the pressure of a given amount of gas is directly proportional to its temperature on the Kelvin scale when volume and number of moles are held constant
Gay-Lussac's law assumes that __________.
the volume is held constant the number of moles is held constant
Dalton's Law
total pressure of a mixture is ideal gases is equal to the sum of the partial pressures of the compound gases
