Chemistry Unit 7 Gas Laws + Atmosphere
6.9L
A balloon filled with oxygen gas occupies a volume of 5.5L at 25C. What volume will the gas occupy at 100. C?
107C
A gas thermometer measures temperature by measuring the pressure of a gas inside the fixed volume container. A thermometer reads a pressure of 248 Torr at 0C. What is the temperature when the thermometer reads a pressure of 345 Torr?
122 mL
A helium-filed balloon contains 125 mL of a gas at a pressure of 0.974 atm and 0C. What volume will the gas occupy at STP?
because they wouldn't be able to compare the two unless they converted the rocky mountains to sea level pressure
Air pressure is converted to sea level pressure to observe surface low and high pressures. Otherwise the rocky mountains would always be low pressure and the oceans would be areas of high pressure. Why is that?
1.19L
Ammonia can react with oxygen to produce Nitrogen and water: 4NH3 + 3O2 --> 2N2 + 6H2O. If 1.78L of O2 reacts, what volume of nitrogen will be produced? Assume temperature and pressure are constant.
2000 mL
An ideal gas has a volume of 500 mL at 1 atm and 0C. What volume will it occupy at 546K and 0.5 atm? Assume number of particles is constant.
it increases
As the temperature of a gas increases, what happens to its kinetic energy?
directly
At a constant volume, the pressure of a fixed mass of any gas is _________________ proportional to its Kelvin temperature.
it stops
At absolute zero, which is a hypothetical temperature, what happens to molecular movement?
more
At lower altitudes is there more or less atmospheric pressure?
14.7 psi
At sea level, what is the average weight of air above a unit area of 1 square inch in psi (lbs/sq inch)?
at high temperatures and low pressure
At what conditions are real gases similar to ideal gases?
1.09 atm
Consider a container with a volume of 22.4L filled with a gas at 1.00 atm at 273K. What will be the new pressure if the temperature increases to 298K?
yes
Do real gases behave like ideal gases under most ordinary conditions?
less molecules higher up makes it harder to breath because there is not as much oxygen to be able to be breathed in
Does less molecules higher up make it harder or easier to breath than at sea level? Why?
more molecules higher up makes it easier to breath because you can get more oxygen with each breath
Does more molecules higher up make it harder or easier to breath than at sea level? Why?
the density of molecules decreases with height because there is less air pushing down from above and gravity is weaker father from Earth's center, so the molecules spread out more, which decreases their density
Does the density of molecules decrease or increase with height? Why?
molecules of greater than average kinetic energy
During evaporation, what molecules escape from the liquid relating to liquid vapor pressure?
the evaporated liquid
For liquids in a closed container, what is the liquid vapor pressure caused by?
a column of mercury is pushed upwards a certain height depending on the atmospheric pressure. the height of the mercury is the atmospheric pressure.
How does a barometer measure atmospheric pressure?
1.013 Bar
How many bars are in 1 atm?
101.3 kPa
How many kilopascals are in 1 atm?
760 mm Hg
How many millimeters of Mercury are in 1 atm?
101,325 Pa
How many pascals are in 1 atm?
760 torr
How many torr are in 1 atm?
it will have the same proportion because, at a given temperature and pressure, equal volumes contain an equal number of moles, independent of the kind of gas
If pressure and temperature are held constant, what happens to the volume of the gas if you increase the number of particles?
volume decreases because there is less pressure pushing against the atmospheric pressure, causing the container that the gas is in to be compressed
If the number of moles and temperature is constant, what happens to the volume of a gas if you decrease the pressure and why?
volume increases because there is more pressure pushing against the atmospheric pressure, causing the container that the gas is in to expand
If the number of moles and temperature is constant, what happens to the volume of a gas if you increase the pressure and why?
lower because water vapor is lighter than nitrogen and oxygen
If there is a higher water vapor content, will atmospheric pressure be higher or lower and why?
the atmospheric pressure is greater
In a manometer if the level of mercury is higher on the container side, what is the pressure of the gas in the container compared to the atmospheric pressure?
the pressure in the container is greater
In a manometer if the level of mercury is lower on the container side, what is the pressure of the gas in the container compared to the atmospheric pressure?
it is the same
In a manometer if the level of mercury is the same on both sides of the u-tube, what is the pressure of the gas in the container compared to the atmospheric pressure?
2250
In the balanced chemical reaction for the fermentation of glucose: C6H12O6 --> 2CO2 + 2C2H5OH, how many grams of glucose are needed to produce 25 moles of ethanol?
2 to 2
In the balanced chemical reaction for the fermentation of glucose: C6H12O6 --> 2CO2 + 2C2H5OH, what is the mole ratio of carbon dioxide to ethanol?
24.9L
In the balanced chemical reaction for the fermentation of glucose: C6H12O6 --> 2CO2 + 2C2H5OH, what volume of carbon dioxide is produced when 100 grams of glucose is fermented to ethanol at STP?
lower
Is air pressure lower or higher at high elevations?
896L
The industrial production of ammonia is N2 + 3H2 --> 2NH3. If 20.0 mol of nitrogen is available, what volume of NH3 at STP can be produced?
0.17 atm
The volume occupied by a gas at constant temperature and 1 atm is 250L. At what pressure (in atm) will the gas occupy 1500L?
14.6 mL
The volume of a gas at 27.0C and 0.200 atm is 80.0 mL. What volume will the gas sample occupy at standard conditions?
180L
The volume of an ideally behaving gas is 300L at 227C. What volume will the gas occupy at 27C? Assume pressure and number of particles are constant.
true
True or false: gases are much less dense than solids and liquids.
they have mass, they are very small, and most gases are diatomic molecules
What 3 things does the kinetic molecular theory say about gases?
gas particles do not exert forces on each other, there is no attraction or repulsion between particles, and collisions are elastic, which means no energy is lost between molecules and container
What 3 things does the kinetic molecular theory say about the elastic collisions of gases?
nitrogen and oxygen
What are the 2 main gases that make up the Earth's atmosphere?
they have mass but very small volume, they move randomly in straight lines, they are not subject to any attractive or repulsive force, and their collisions are perfectly elastic (no energy is lost during a collision)
What are the 4 properties of ideal gases?
the amount of gas, volume, temperature, and pressure
What are the 4 variables of gases?
they are compressible, they are fluid, they have low density, they mix homogeneously with other gases, and they occupy a very small volume of their container
What are the 5 properties of a gas?
the temperature should always be in Kelvin
What do you have to remember about temperature in all gas law calculations?
if the temperature of a given gas sample remains unchanged, the product of the pressure times the volume has a constant value
What does Boyle's law state?
the total pressure of a mixture of gas is the sum of the pressures of each gas
What does Dalton's law of partial pressures state?
no energy is lost between molecules and the container that the gas is in
What does it mean for a collision to be elastic?
kinetic energy
What does temperature of a gas depend on?
they are far apart from each other relative to their size
What does the kinetic molecular theory say about the molecular distance of gases?
they are in constant, rapid motion
What does the kinetic molecular theory say about the molecular motion of gases?
they are compressed
What happens to gases when pressure is exerted on them?
it is either absorbed or reflected
What happens to the energy from the sun once it reaches the Earth's surface?
it increases because raising the temperature increases the kinetic energy of molecules, so the molecules will collide with the walls more frequently, which means the collisions will push back the walls, allowing the gas to occupy a greater volume than before
What happens to the volume of a gas if you raise the temperature of a gas and why?
barometer
What instrument is used to measure atmospheric pressure?
a temperature scale designed so that zero degrees K is defined as absolute zero
What is Kelvin?
an instrument that is used to measure the pressure in a closed container
What is a manometer?
barometric pressure
What is another name for atmospheric pressure?
force/unit area pushed against a surface by the weight of the air above that surface
What is atmospheric pressure?
the force of gas particles colliding with the walls of the container they are in
What is gas pressure?
energy that results from motion
What is kinetic energy?
mass/molar mass
What is n equal to relating to molar mass?
the continuous physical force exerted on or against an object by something in contact with it
What is pressure?
0C and 1 atm
What is standard temperature and pressure?
a measure of the average kinetic energy of molecules
What is temperature?
pascal
What is the SI unit of pressure?
V1/n1 = V2/n2
What is the equation for Avogadro's Law?
P1V1 = P2V2
What is the equation for Boyle's Law?
V1/T1 = V2/T2
What is the equation for Charles' Law?
K = C + 273
What is the equation for Kelvin?
kinetic energy = 1/2(mass)(velocity)^2
What is the equation for kinetic energy?
force/area
What is the equation for pressure?
P1V1/T1 = P2V2/T2
What is the equation of the combined gas law?
P1/T1 = P2/T2
What is the equation relating pressure and temperature?
gas particles have mass because they are made of atoms and molecules
What is the first main point of the kinetic molecular theory?
balance the equation
What is the first step for all gas stoichiometry problems?
temperature is a measure of the average kinetic energy of the gas
What is the fourth main point of the kinetic molecular theory?
PV = mRT/M
What is the ideal gas equation relating to mass and molar mass?
PV = nRT
What is the ideal gas equation?
83.8g/mol
What is the molar mass of a gas if 0.427g of the gas occupies a volume of 125 mL at 20.0C and 0.980 atm?
gas particles are far apart from each other and are in constant, rapid, random motion
What is the second main point of the kinetic molecular theory?
gas particles bounce off each other and the walls of the container they are in without losing kinetic energy
What is the third main point of the kinetic molecular theory?
6.17L
What is the volume, in L, of 0.250 mol of O2 gas at 20.0C and 740.24 mm Hg of pressure?
68.7g
What mass of ethene gas, C2H2, is contained in a 15.0L tank that has a pressure of 4.40 atm and a temperature of 305K?
noble gases
What type of gases do not bond with any other atoms under ordinary conditions?
29.8L
When arsenic (III) sulfide is baked in air, it reacts with oxygen to produce arsenic (III) oxide and sulfur dioxide: 2As2S3 + 9O2 --> 2As2O3 + 6SO2. When 98.5g of As2S3 is baked in excess oxygen, what volume of SO2 is produced? The gaseous product is measured at 20C and 98.0 kPa.
when the liquid level remains constant, and no more liquid is being evaporated
When can you tell that you've reached liquid vapor equilibrium?
when the equilibrium vapor pressure is reached
When do molecules in the vapor phase stop exerting pressure?
at the areas that are farthest away from the sun like the north and south poles
Where is solar radiation the weakest?
at the areas that are closest to the sun like the equator
Where is the solar radiation the strongest?
because there is a lot of empty space between gas particles
Why are gases easily compressed?
because you are adding more gas particles into the balloon, and since there are more gas particles there will be more collisions, which means the force exerted per unit area is greater, so the pressure is increased. when the pressure inside the balloon is increased, it pushes against the atmospheric harder, causing the balloon to expand.
Why do balloons get bigger as you blow it up?
because they are in constant, rapid motion
Why do gases fill containers so quickly?
because at high pressures the gas is compressed more and more, so as volume decreases the gas particles become more of a significant proportion of the total volume of gas, which does not match the kinetic molecular theory, which states that gases are very small
Why do gases not obey the ideal gas equation at high pressures?
because at low temperatures the gas particles slow down, so the attractive forces between the become significantly larger, which does not match the kinetic molecular theory, which states that there are no attractive forces between gases
Why do gases not obey the ideal gas equation at low temperatures?
because as temperature increases gas particles will move around more rapidly, so the collisions with the side of the container will be more forceful, and since pressure is force exerted on a unit area if the area stays the same and force is increased, then pressure is increased
Why does pressure increase when temperature increases?
because as temperature is increased more of the liquid changes into vapor state, which increases vapor pressure
Why does vapor pressure increase as temperature goes up?
