CHEM Chapter 9 SmartBooks
Based on the graph of temperature vs. volume, select all the temperature changes that would cause the volume an ideal gas occupies to double.
-273 K to 546 K -25°C to 323°C
Select all of the statements that correctly describe the relationship between pressure and volume at constant temperature.
-As volume decreases, gas particles in a smaller space strike the walls more frequently, increasing the pressure. -Decreasing the volume a gas occupies will increase the pressure it exerts.
Select all statements that accurately describe mixtures of ideal gases.
-Each gas exerts its own pressure. -Each gas behaves as if it were alone.
Select all statements that accurately describe diffusion and effusion.
-Effusion requires gas particles to pass through a small opening. -Diffusion is the movement of gas particles into regions of lower concentration.
Select all of the following that are postulates of kinetic-molecular theory.
-Gas particles are small and very spread out. -Gas particles move rapidly and in straight lines, except when colliding.
Select all of the statements that correctly describe the properties of gases.
-Gases expand to fill their containers. -Gas particles are not strongly attracted to each other. -Gases are less dense than liquids and solids.
Select all the statements that accurately describe the ideal gas constant R.
-It has a value of 0.08206. -It has units of L⋅atmmol⋅K
Select all statements that accurately describe the molar volume of an ideal gas.
-It is the volume occupied by 1 mole of the gas. -It has a value of 22.414 L at 0°C and 1 atm. -It is equal for all ideal gases under the same conditions.
Match the proper units to each variable in the ideal gas law.
-P = atm -V = L -n = mol -T = K
Which of the following statements correctly describe gas pressure? Select all that apply.
-Pressure is caused by gas particles striking the walls of the container. -Adding more gas to a container will increase the pressure inside.
Which of these conditions are part of the definition of STP? Select all that apply.
-T = 0°C -P = 1 atm
Select all of the statements that correctly describe the combined gas law.
-V and T are directly related. -P and T are directly related.
A piston is filled with 1.0 L of gas at a pressure of 1.0 atm. Select all outcomes that are possible if the absolute temperature of the gas doubles.
-V becomes 4.0 L while P becomes 0.5 atm. -V becomes 2.0 L while P remains 1 atm. -P becomes 2.0 atm while V remains 1.0 L.
If the pressure and temperature of an ideal gas are known, select all of the following that must also be known to calculate the mass of gas present.
-Volume of the gas -Identity of the gas
Select all units that are commonly used to represent pressures.
-mm Hg -atm -lb/in^2
Select all the properties that are commonly used to describe gases.
-number of particles -temperature -pressure
Select all of the following relationships that contribute to the ideal gas constant.
-va 1/p -va T -va n
A student collects 0.883 L of hydrogen gas over water. If the room temperature is 23.0°C and the pressure is 772 torr, how many moles of hydrogen were collected? The table shown gives the vapor pressure of water at various temperatures.
0.0359 mol PH2 = 772 torr-21.1 torr760 torr/atm772 torr-21.1 torr760 torr/atm = 0.988 atm. nH2 = PVRTPVRT = (0.988 atm)(0.883 L)(0.08206 atm⋅L/mol⋅K)(296.2 K)(0.988 atm)(0.883 L)(0.08206 atm⋅L/mol⋅K)(296.2 K) = 0.0359 mol
Nitrogen gas can be generated by the decomposition of sodium azide, NaN3. In a particular reaction, 2.04 L of N2 were collected over water at 35oC and an atmospheric pressure of 755 torr. How many moles of N2 were collected? The table shown gives the vapor pressure of water at various temperatures.
0.0757 mol PN2 = 755torr-42.2torr760torr/atm755torr-42.2torr760torr/atm = 0.938 atm. nN2 = PVRTPVRT = (0.938atm)(2.04L)(0.08206atm⋅L/mol⋅K)(308.2K)(0.938atm)(2.04L)(0.08206atm⋅L/mol⋅K)(308.2K) = 0.0757 mol
How many moles of O2 can be found in 2.63 L at 48.0°C and a pressure of 815 torr?
0.107 mol P = (815 torr)815 torr(1 atm760 torr)1 atm760 torr = 1.07 atm T = 48.0°C + 273.15 = 321.2 K PV = nRT n = PVRTPVRT n = (1.07 atm)(2.63 L)(0.0821L⋅atmmol⋅K)(321.2 K)1.07 atm2.63 L0.0821L⋅atmmol⋅K321.2 K n = 0.107 mol
A sample of SF6 gas in an expandable container occupies 1.75 L at 0.950 atm and 37.0°C. If the temperature is increased to 65.0°C and the volume decreases to 1.18 L, what pressure will the SF6 exert?
1.54 atm P1V1T1P1V1T1 = P2V2T2P2V2T2 (0.950 atm)(1.75 L)310.2 K(0.950 atm)(1.75 L)310.2 K = P2(1.18 L)338.2 KP2(1.18 L)338.2 K P2 = 1.54 atm
What is the density of 2.10 L of nitrogen gas with a mass of 3.95 g?
1.88 g/L Density is mass/volume
What volume do 0.450 moles of H2 gas occupy at STP conditions? (Standard molar volume = 22.414 L/mol)
10.1 L (0.450 mol H2)(22.414 L1 mol)22.414 L1 mol = 10.1 L
An inflatable ball has a volume of 10.0 mL at a temperature of 10.0°C. If the temperature is raised to 30.0°C at constant pressure, what is the new volume of the ball?
10.7 mL V1T1V1T1 = V2T2V2T2 V2 = V1T2T1V1T2T1 V2 = (10.0 mL)(303.2 K)283.2 K(10.0 mL)(303.2 K)283.2 K = 10.7 mL
A sealed syringe contains 15.0 mL of N2 at atmospheric pressure (760 torr). If the pressure is increased to 985 torr, what is the new volume of the syringe?
11.6 mL P1V1 = P2V2 (760 torr)(15.0 mL) = (985 torr)V2 V2 = 11.6 mL
Express a pressure of 147.0 kPa in mm Hg. 1 atm = 101.325 kPa 1 atm = 760 mm Hg
1103 mm Hg 147.0 kPa(1 atm101.325 kPa)1 atm101.325 kPa = 1.451 atm 1.451 atm(760 mm Hg1 atm)760 mm Hg1 atm = 1103 mm Hg
Convert an atmospheric pressure of 30.5 inches of mercury to pounds per square inch. 1 atm = 29.9 in Hg 1 atm = 14.7 lb/in2
15.0 lb/in2 30.5 in Hg × 1 atm29.9 in Hg1 atm29.9 in Hg × 14.7 lb/in21 atm14.7 lb/in21 atm = 15.0 lb/in2
Determine the molar volume of Ar gas at -20.0°C and 1.35 atm. (Standard molar volume = 22.414 L/mol)
15.4 L P1V1T1P1V1T1 = P2V2T2P2V2T2 V2 = P1V1T1P1V1T1T2P2T2P2 V2 = (1.00 atm)(22.414 L)273.15 K(1.00 atm)(22.414 L)273.15 K(253.2 K)(1.35 atm)(253.2 K)(1.35 atm) = 15.4 L
A syringe with a moveable piston contains 3.88 x 10-3 moles of argon in a volume of 105 mL. If the volume of the syringe is reduced to 65 mL at constant temperature and pressure, how many moles of argon will it contain?
2.4 x 10-3 moles n2 = n1V2V1n1V2V1 = (3.88 x 10-3 mol)(0.065 L)0.105 L(3.88 x 10-3 mol)(0.065 L)0.105 L = 2.4 x 10-3 mol
Hydrogen gas (H2) can be generated from zinc and hydrochloric acid according to the reaction shown below. What mass of zinc will react with an excess of HCl to generate 0.825 L of hydrogen gas at STP? Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
2.41 g nH2 = PVRTPVRT = (1.00 atm)(0.825 L)(0.08206 atm⋅L/mol⋅K)(273.2 K)(1.00 atm)(0.825 L)(0.08206 atm⋅L/mol⋅K)(273.2 K) = 0.0368 mol 0.0368 mol H2 × 1 mol Zn1 mol H21 mol Zn1 mol H2 × 65.38 g Zn1 mol Zn65.38 g Zn1 mol Zn = 2.41 g Zn
Propane gas from a tank is burned in air according to the reaction below. The combustion consumes 3.75 L of C3H8 at 15.0 atm and 22.0°C. If CO2 is produced at 1.06 atm and 148°C, what volume of CO2 will result? C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)
227 L CO2 Follow these steps: 1. Use the ideal gas law to find moles of C3H8. 2. Use the balanced reaction to find moles of CO2. 3. Use the ideal gas law to find the volume of CO2.
Determine the molar volume of Ne gas at 52.0°C and 1.10 atm. (Standard molar volume = 22.414 L/mol)
24.3 L/mol V2 = P1V1T2P2T1P1V1T2P2T1 = (1.00 atm)(22.414 L)(325.2 K)(1.10 atm)(273.15 K)(1.00 atm)(22.414 L)(325.2 K)(1.10 atm)(273.15 K) = 24.3 L
Ammonia can be produced according to the following reaction. According to Gay-Lussac's law of combining volumes, how many volumes of H2 would react with each volume of N2? N2(g) + 3H2(g) → 2NH3(g)
3 volumes
The density of an unknown gas is determined to be 2.95 g/L at STP. What is the molar mass of the gas?
66.1 g/mol The molar volume at STP is 22.414 L. 2.95 g1 L2.95 g1 L x 22.414 L1 mol22.414 L1 mol = 66.1 g/mol
Given that PV = nRT (the ideal gas law), what are the units of the ideal gas constant R?
L⋅atm/mol⋅K
Propane gas (C3H8) burns in oxygen to form carbon dioxide and water vapor according to the equation shown below. According to Gay-Lussac's law of combining volumes, one volume of propane will combine with ______ volume(s) of oxygen to produce a total of ______ volumes of products. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)
five; seven
What is the proper setup to convert a pressure of 2.50 atm into torr?
(2.50 atm)2.50 atm(760 torr1 atm)760 torr1 atm = 1.90×103 torr
At what temperature will a gas have the highest density, given the same pressure and number of gas particles?
-15°C
A 5.0-L bottle contains a mixture of N2, Cl2, and H2O gases. According to Dalton's law of partial pressures, if the partial pressures of the gases are PN2 = 0.448 atm, PCl2 = 0.169 atm, and PH2O = 0.137 atm, what is the total pressure exerted on the bottle?
0.754 atm The total pressure is the su, of all partial pressures.
A balloon is inflated to a volume of 1.3 L and is found to contain 0.14 mol of a gas. If another balloon is inflated to 7.2 L at the same pressure and temperature, how many moles of gas are present in the second balloon?
0.775 mol V1n1V1n1 = V2n2V2n2 n2 = V2n1V1V2n1V1 n2 = (7.2 L)(0.14 mol)1.3 L(7.2 L)(0.14 mol)1.3 L = 0.775 mol
A container with a moveable piston contains 2.35 L of helium at a pressure of 1.25 atm. What will the new pressure be if the volume is increased to 3.50 L?
0.839 atm P2 = P1V1V2P1V1V2 = (1.25 atm)(2.35 L)3.50 L(1.25 atm)(2.35 L)3.50 L = 0.839 atm
Arrange these gases in order of increasing velocity at a given temperature. The fastest gas should be at the top of the list.
1. NH3 2. O2 3. Ar 4. SF6
Rank the following from highest to lowest pressure, with the highest at the top.
1.) 20 lb exerted over 10 in^2 2.) 15 lb exerted over 10 in^2 3.) 15 lb exerted over 20 in62 4.) 70 lb exerted over 100 in^2
A sample of hydrogen gas in a compressible container occupies a volume of 825 mL at 21oC and 1.00 atm. What will its pressure be if the container is heated to 52oC and the volume is changed to 655 mL?
1.39 atm P2 = P1V1T2V2T1P1V1T2V2T1 = (1.00 atm)(0.825 L)(325 K)(0.655 L)(294 K)(1.00 atm)(0.825 L)(325 K)(0.655 L)(294 K) = 1.39 atm
A particular balloon has a volume of 4.50 L at a temperature of 21.5oC. What will its volume be if it is cooled in a freezer to -4.0oC?
4.11 L V2 = V1T2T1V1T2T1 = (4.50 L)(269.2 K)(294.7 K)(4.50 L)(269.2 K)(294.7 K) = 4.11 L
What volume do 2.70 moles of Ne gas occupy at STP conditions? (Standard molar volume = 22.414 L/mol)
60.5 L (2.70 mol Ne)(22.414 L1 mol)22.414 L1 mol = 60.5 L
If 2.87 L of N2 at 13.8°C and 699 torr react with excess Li, how many grams of Li3N form? 6Li(s) + N2(g) → 2Li3N(s)
7.80 g Li3N PN2 = 699 torr760 torr/atm699 torr760 torr/atm = 0.920 atm nN2 = PVRTPVRT = (0.920 atm)(2.87 L)(0.08206 atm⋅L/mol⋅K)(287.0 K)(0.920 atm)(2.87 L)(0.08206 atm⋅L/mol⋅K)(287.0 K) = 0.112 mol 0.112 mol N2 × 2 mol Li3N1 mol N22 mol Li3N1 mol N2 × 34.83 g Li3N1 mol Li3N34.83 g Li3N1 mol Li3N = 7.80 g Li3N
What mass of SF6 (molar mass = 146.06 g/mol) can be found in a 15.0-L tank at STP?
97.7 g PV = nRT n = PVRTPVRT = (1 atm)(15.0 L)(0.0821)(273.15 K)(1 atm)(15.0 L)(0.0821)(273.15 K) = 0.669 mol (0.669 mol)(146.06 g1 mol)146.06 g1 mol = 97.7 g
What is the term for a gas that behaves according to linear relationships, such as PV = constant?
An ideal gas.
This graph shows the relationship between temperature and volume for an ideal gas. If a gas begins at point C on the graph and its absolute temperature is decreased by a factor of 4 at constant pressure, which point shows the new temperature and volume of the gas?
B
An unknown ideal gas is found to have a density of 3.16 g/L at STP. What could the gas be? Molar masses are listed after each gas.
Cl2 (70.906 g/mol)
According to Avogadro's hypothesis, which of the following is correct for a gas at constant pressure and temperature?
Doubling the number of gas particles present will double the volume the gas occupies.
True or false: If S8 and O2 react to form SO2 according to the equation below, then 8.0 L of O2 gas will always produce 8.0 L of SO2. S8(s) + 8O2(g) → 8SO2(g)
False Avogadro's law only applies at constant P and T. If either of these change during the reaction, 8.0 L of O2 will not produce 8.0 L of SO2.
Which phase of matter has a density that strongly depends on pressure and temperature?
Gas
Which of the following explains why gases can be compressed?
Gases have large empty spaces between particles.
Which statement correctly explains why different gases under the same conditions diffuse at different rates?
Gases with different masses have different average velocities.
A reaction occurs inside a 5.0-L balloon. At the end of the reaction, the pressure and temperature are the same as at the beginning, but the volume is now only 2.5 L. According to Avogadro's hypothesis, what happened?
Half of the gas inside was consumed.
Why does gas density change with temperature?
Higher temperature causes gas particles to move more rapidly, causing them to spread further apart.
Which of the following correctly describes the pressure, volume, temperature, and number of particles of a gas?
If one changes, at least one of the others will also change.
Three balloons contain samples of NH3, H2S, and C6H6 gases. If the three balloons are simultaneously popped on the other side of the room, which gas would you smell first?
NH3
Which of these gases would have the highest average kinetic energy?
NO2 at 33°C Average kinetic energy of an ideal gas depends only on temperature.
If a bicycle pump is compressed and the volume decreases to 1/16 of the original volume, what happens to the gas inside, assuming a constant temperature?
The pressure increases by a factor of 16.
Based on these graphs of pressure vs. volume, predict what will happen to the pressure of an ideal gas if its volume is doubled.
The pressure will decrease to half.
Which of the following correctly describes how Charles's law relates the temperature and volume of an ideal gas?
The relationship is true only at constant pressure.
If 1 mole of each of these three ideal gases is present at a temperature of 0°C and a pressure of 1 atm, which will occupy the most volume?
They occupy equal volumes.
True or false: All ideal gases have a molar volume of 22.414 L/mole at STP conditions.
True
If the temperature of a flexible, gas-filled container is decreased at a fixed pressure, the volume of the container will ______.
decrease
Which is the proper setup for determining the number of moles of an ideal gas, given P, V, and T.
n = PV/RT.
