Chapter 5: Gases Test Bank
Calculate the density of F2 gas at 26°C and 755 torr.
1.54 g/L
Toy balloons are filled with hydrogen gas, at standard temperature, from a 10.0-liter cylinder. The initial pressure of the gas in the cylinder is exactly 100 atm. Assuming each balloon is filled to a volume of 1.0 liter at standard pressure, how many balloons could be filled?
9990 balloons
A 3.31-g sample of lead nitrate, , molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 2.37 L. The salt decomposes when heated, according to the equation: 2Pb(NO3)2(s) --> 2PbO(s) + 4NO2(g) + O2(g) Assuming complete decomposition, what is the pressure in the cylinder after decomposition and cooling to a temperature of 300. K? Assume the takes up negligible volume.
a) 0.260 atm
The local weather forecaster reports that the current barometric pressure is 30.4 inches of mercury. What is the current pressure in atmospheres?
a) 1.02 atm
What is the density of oxygen gas, in g per liter, at 25°C and 0.850 atm?
a) 1.11
A sample of a gas occupies a volume of 2.62 liters at 25 °C and 1.00 atm. What will be the volume at 50.0 °C and 2.00 atm?
a) 1.42 liters
A sample of oxygen gas has a volume of 1.72 L at 27 C and 800.0 torr. How many oxygen molecules does it contain?
a) 4.43
A 7.94 g piece of solid CO2 (dry ice) is allowed to sublime in a balloon. The final volume of the balloon is 1.00 L and 301 K. What is the pressure of the gas?
a) 4.46 atm
An automobile tire is filled with air at a pressure of 27.0 lb/in2 at 25 C. A cold front moves through and the temperature drops to 5 C. Assuming no change in volume, what is the new tire pressure?
b) 25.2 lb/in2
What volume is occupied by 21.0 g of methane (CH4) at 27 C and 1.25 atm?
b) 25.8 L
The mass of 1.12 liters of gas Y at STP is found to be 6.23 g. The density of gas Y is
b) 5.56 g/L
The air pressure in the inner tube of a tire on a typical racing bike is held at a pressure of about 112 psi. Convert this pressure to atm.
b) 7.62 atm
A 1.00-g sample of a gaseous compound of boron and hydrogen occupies 0.820 L at 1.00 atm and 3°C. What could be the molecular formula for the compound?
b) B2H6
For which gas are the molecules diatomic?
b) Cl2
Which gas has the highest density?
b) Cl2
For an ideal gas, which pairs of variables are inversely proportional to each other (if all other factors remain constant)? 1. V and T 2. T and n 3. n and V 4. P and T
c) 2 only
What will be the pressure of a sample of 48.0 grams of oxygen gas in a glass container of volume 5.2 L at 25 °C?
c) 7.05 atm
A sample of gas occupies 20.0 liters at 32 °C when the pressure is 0.750 atm. What temperature in °C is required to increase the volume to 25.0 liters at a pressure of 0.680 atm?
c) 72.7°C
One way to isolate metals from their ores is to react the metal oxide with carbon as shown in the following reaction: 2MO(s) + C(s) --> 2M(s) + CO2(g) If 34.08 g of a metal oxide reacted with excess carbon and 4.37 L of CO2 formed at 100°C and 1.50 atm, what is the identity of the metal?
c) Cu
At 200 K, the molecules or atoms of an unknown gas, X, have an average velocity equal to that of Ar atoms at 400 K. What is X? (Assume ideal behavior.)
c) HF
The temperature of a specfic amount of gas in a sealed container changes from 20.0 C to 40.0 C. If the volume remains constant, the pressure will change from 755 mmHg to
d) 807 mmHg
Which of the following would have a higher rate of effusion than C2H2? a) N2 b) O2 c) Cl2 d) CH4 e) CO2
d) CH4
A gas is found to diffuse at half the rate of methane (CH4). Which of the following could be this gas?
d) SO2
In which flask is there 0.039 mol of gas?
d) all
Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. Which contains the largest number of molecules?
d) all are the same
Which of the following statements is false? a) the density of a gas is directly proportional to the external pressure. b) the density of helium gas is double that of hydrogen gas. c) the density of a gas is indirectly proportional to the temperature in Kelvin. d) all gases have the same density at STP. e) the density of a gas is independent of the volume.
d) all gases have the same density at STP.
The SI unit of pressure is the
pascal
Mercury vapor contains Hg atoms. What is the volume of 201 g of mercury vapor at 822 K and 0.512 atm?
a) 132 L
You are holding four identical balloons each containing 10.0 g of a different gas. The balloon containing which gas is the largest balloon?
a) H2
Calculate the ratio of the effusion rates of N2 and N2O
c) 1.25
Given the reaction 2NH3(g) + 3Cl2(g) --> N2(g) + 6HCl(g), you react 5.0 L of NH3 with 5.0 L of Cl2 measured at the same conditions in a closed container. Calculate the ratio of pressures in the container (Pfinal/Pinitial).
c) 1.33
You have a 400-mL container containing 55.0% He and 45.0% Ar by mass at 25°C and 1.5 atm total pressure. You heat the container to 100°C. Calculate the total pressure.
c) 1.88 atm
Which of the following would represent the greatest pressure? a) 0.680 atm b) 517 mmHg c) 11.4 psi d) 62106 Pa e) 14.1 in Hg
c) 11.4 psi
The mass of 1.12 liters of gas Y at STP if found to be 6.23 g. The molar mass of gas Y is
c) 125 g/mol
The ratio of the number of moles of gas in the first container compared to that in the second is
c) 1:4
Argon has a density of 1.78 g/L at STP. How many of the following of the gases have a density at STP greater than that of argon? Cl2, He, NH3, NO2
c) 2
The valve between the 2.00-L bulb, in which the gas pressure is 1.80 atm, and the 3.00-L bulb, in which the gas pressure is 3.00 atm, is opened. What is the final pressure in the two bulbs, the temperature remaining constant?
c) 2.52 atm
A 3.60 L sample of carbon monoxide is collected at 55 C and 0.869 atm. What volume will the gas occupy at 1.05 atm and 25 C?
c) 2.71 L
You have 41.6 g of O2 gas in a container with the twice the volume as one with Co2 gas. The pressure and temperature of both containers are the same. Calculate the mass of carbon dioxide gas you have in the container.
c) 28.6 g
Which of the following pollutant gases is not produced directly in a combustion engine?
c) O3
If equal masses of hydrogen gas and helium gas are placed in the same container, determine the ratio of partial pressure of hydrogen : partial pressure of helium.
2
A sample of an unknown gas takes 434 s to diffuse through a porous plug at a given temperature. At the same temperature, N2(g) takes 175 s to diffuse through the same plug. What is the molar mass of the unknown gas?
a) 172 g/mol
You are holding two balloons, an orange balloon and a blue balloon. The orange balloon is filled with neon (Ne) gas and the blue balloon is filled with argon (Ar) gas. The orange balloon has twice the volume of the blue balloon. Which of the following best represents the mass ratio of Ne:Ar in the balloons?
a) 1:1
Calcium hydride combines with water according to the equation: CaH2(s) + 2H2O(l) --> 2H2(g) + Ca(OH)2(s) Beginning with 84.0 g of CaH2 and 42.0 g of H2O, what volume of H2 will be produced at 273 K and a pressure of 1327 torr?
a) 29.9 L
A mixture of KCl and KClO3 weighing 1.34 grams was heated; the dry O2 generated occupied 143 mL at STP. What percent of the original mixture was KClO3, which decomposes as follows: 2KClO3(s) --> 2KCl(s) + 3O2(g)
a) 38.9%
It is found that 250. mL of a gas at STP has a mass of 0.700 g. What is the molar mass?
a) 62.7 g/mol
A chemical reaction produced 10.1 cm3 of nitrogen gas at 23 °C and 746 mmHg. What is the volume of this gas if the temperature and pressure are changed to 0 °C and 760 mmHg?
a) 9.14 cm3
Order the following in increasing rate of effusion: F2, Cl2, NO, NO2, CH4
a) Cl2 < NO2 < F2 < NO < CH4
Of all the following real gases, which would be expected to have the lowest van der Waals correction for intermolecular attractions?
a) H2
For which gas do the molecules have the highest average velocity?
a) He
A 3.54 gram sample of a certain diatomic gas occupies a volume of 3.30-L at 1.00 atm and a temperature of 45°C. Identify this gas.
a) N2
If M is the molar mass, R the gas constant, T the temperature, and P its pressure, which of the following expressions represents the density of a gas?
a) PM/RT
At 1000°C and 10. torr, the density of a certain element in the gaseous state is . The element is:
c) Na
Charles's law states that:
c) the volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure
Consider a sample of helium gas in a container fitted with a piston, as pictured below. The piston is frictionless, but has a mass of 10.0 kg. How many of the following processes will cause the piston to move away from the base and decrease the pressure of the gas. Assume ideal behavior.
b) 1
Body temperature is about 309 K. On a cold day, what volume of air at 276 K must a person with a lung capacity of 2.2 L breathe in to fill the lungs?
b) 1.97 L
A balloon contains an anesthetic mixture of cyclopropane (cp) and oxygen (O2) at 171 torr and 570. torr, respectively. What is the ratio of the number of moles of cyclopropane to moles of oxygen? ncp/nO2 = ?
c) 0.300
Gaseous reacts with according to the following equation: C2H4(g) + 3O2(g) --> 2CO2 + H2O(g) What volume of oxygen gas at STP is needed to react with 5.75 mol of ?
c) 3.86 x 10^2 L
What volume does 40.5 g of N2 occupy at STP?
c) 32.4 L
You fill a balloon with 2.50 moles of gas 22 C at a pressure of 1.62 atm. What is the volume of the balloon?
c) 37.4
Zinc metal is added to hydrochloric acid to generate hydrogen gas, which is collected over a liquid whose vapor pressure is the same as pure water at 20.0°C (18 torr). The volume of the gas mixture is 1.7 L and its total pressure is 0.810 atm. Determine the partial pressure of the hydrogen gas in this mixture.
c) 598 torr
The rate of effusion of an unknown gas was measured and found to be 11.9 mL/min. Under identical conditions, the rate of effusion of pure oxygen (O2) gas is 14.0 mL/min. Based on this information, the identity of the unknown gas could be:
c) CO2
Combustion of coal releases sulfur dioxide into the atmosphere. The following process converts this gas into sulfuric acid, a component of acid rain. 2SO2(g) + O2(g) --> 2SO3(g) SO3(g) + H2O(l) --> H2SO4(aq) If each tonne of coal produces L of sulfur dioxide (measured at STP), what mass of sulfuric acid can result from combustion of each tonne of coal? (1 tonne = 1000 kg)
d) 5.69 x 10^1 kg H2SO4
Complete the following: Because real gas particles have attraction for one another:
d) real gases act more ideally at higher temperatures and lower pressures.
The van der Waals equation, nRT = [P + a(n/V)2] (V - nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for
d) the finite volume of molecules
Which of the following effects will make PV/nRT less than one for a real gas? a) the gas molecules are large enough to occupy a substantial amount of space. b) a large number of molecules have speeds greater than the average speed. c) the gas molecules have a very low molar mass. d) the gas molecules attract one another. e) none of these.
d) the gas molecules attract one another
Dalton's law of partial pressure states that:
c) the volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant temperature
A sample of helium gas occupies 14.7 L at 23 C and 0.956 atm. What volume will it occupy at 40 C and 1.20 atm?
d) 12.4 L
Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container 1 is 1.30 L.and it contains 6.70 mol of the gas. The volume of container 2 is 2.33 L. How many moles of the gas are in container 2?
a) 12.0 mol
Into a 2.22-liter container at 25°C are placed 1.23 moles of O2 gas and 3.20 moles of solid C (graphite). If the carbon and oxygen react completely to form CO(g), what will be the final pressure in the container at 25°C?
a) 27.1 atm
Gases generally have a) low density b) high density c) closely packed particles d) no increase in volume when temperature is increased e) no decrease in volume when pressure is increased
a) low density
Consider the reaction between ethane (C2H6) and oxygen gas (O2) to produce carbon dioxide and water, as shown. What volume of carbon dioxide will be produced at STP from the reaction of 4.00 L of ethane with 7.00 L of oxygen?
c) 4.00 L CO2
Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 11.8°C. (R = 8.3145 J/K mol)
c) 471.2 m/s
Consider a sample of gas in a container on a comfortable spring day. The Celsius temperature suddenly doubles, and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is a good estimate for the new pressure?
c) 6.4 atm
The valve between a 5-L tank containing a gas at 9 atm and a 10-L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks.
c) 7 atm
When 0.72 g of liquid is vaporized at 110°C and 0.967 atm, the gas occupies a volume of 0.559 L. The empirical formula of the gas is CH2. What is the molecular formula of the gas?
c) C3H6
Consider the following containers, one with helium at 27°C and the other with argon at 27°C. Which of the following statements are true? a) the speed of each atom of helium is 926 m/s. b) the rms speed of the He and the Ar atoms are the same. c) the average kinetic energy of the two samples are equal. d) all of the above are true. e) none of the above are true.
c) the average kinetic energy of the two samples are equal.
A manometer is attached to a sample of gas that occupies a volume of 2.34 liters. The mercury level in arm of the manometer attached to the gas sample is 24.3 torr lower than that of the arm open to the atmosphere. Atmospheric pressure is measured to be 1.23 atm. What is the pressure of the sample of gas?
e) 959 torr
Graham's law states that:
e) the rates of effusion of gases are inversely proportional to the square roots of their molar masses.
Which of the following statements is least likely to be true of a sample of nitrogen gas? a) molecules of gaseous nitrogen are in constant random motion. b) the pressure exerted by gaseous nitrogen is due to collisions of the molecules with the walls of the container. c) the average kinetic energy of the gaseous nitrogen is proportional to the absolute temperature of the gas. d) collisions between the gaseous molecules are elastic. e) the volume of the sample would be zero at -273°C.
e) the volume of the sample would be zero at -273°C.
What volume of carbon dioxide measured at STP will be formed by the reaction of 1.47 mol of oxygen with 0.900 mol of ethyl alcohol, CH3CH2OH?
b) 22.0 L
A room is 16 ft × 12 ft × 12 ft. Would air enter or leave the room if the temperature changed from 27°C to -3°C while the pressure remained constant? Determine the volume of the air that moved in or out of the room.
Air enters the room. 210 ft3 of air moves.
At the same temperature, lighter molecules have a higher average kinetic energy than heavier molecules.
False
Gases behave most ideally at STP.
False
In the kinetic molecular theory we assume an ideal gas has no mass.
False
The diffusion of a gas is faster than the effusion of a gas.
False
The pressure of a gas would exert under ideal conditions is always greater than the observed pressure of a real gas.
False
Avogadro's law states that:
a) equal amounts of gases occupy the same volume at constant temperature and pressure
In which flask do the molecules have the highest average velocity?
a) flask A
Which of the following is not a postulate of the kinetic molecular theory? a) gas particles have most of their mass concentrated in the nucleus of the atom. b) the moving particles undergo perfectly elastic collisions with the walls of the container. c) the forces of attraction and repulsion between the particles are insignificant. d) the average kinetic energy of the particles is directly proportional to the absolute temperature. e) all of the above are postulates of the kinetic molecular theory.
a) gas particles have most of their mass concentrated in the nucleus of the atom.
Calculate the ratio of the rate of effusion of CO2 to He.
b) 0.30/1
The standard temperature for gases is
b) 0°C
Which of the following is included as a postulate in the kinetic molecular theory of an ideal gas? a) the distance between gas molecules is small compared with the size of the molecule. b) all collisions between molecules are elastic. c) in an average collision between molecules, both molecules have the same kinetic energy. d) all molecules move randomly in zigzag directions. e) all the molecules have the same velocity.
b) all collisions between molecules are elastic.
Real gases are those that
b) deviate from ideal behavior
What would happen to the average kinetic energy of the molecules of a gas sample if the temperature of the sample increased from 20°C to 40°C?
b) it would increase
Use the kinetic molecular theory of gases to predict what would happen to a closed sample of a gas whose temperature increased while its volume decreased.
b) its pressure would increase.
Which of the following is true about the kinetic molecular theory? a) the volume of a gas particle is considered to be small - about 0.10 mL. b) pressure is due to the collisions of the gas particles with the walls of the container. c) gas particles repel each other, but do not attract one another. d) adding an ideal gas to a closed container will cause an increase in temperature. e) at least two of the above statements are correct.
b) pressure is due to the collisions of the gas particles with the walls of the container.
Oxygen gas, generated by the reaction is collected over water at 27°C in a 1.55-L vessel at a total pressure of 1.00 atm. (The vapor pressure of H2O at 27°C is 26.0 torr.) How many moles of KClO3 were consumed in the reaction?
c) 0.0405 moles
Which of the following statements is true concerning ideal gases? a) the temperature of the gas sample is directly related to the average velocity of the gas particles. b) at STP, 1.0 L of Ar(g) contains about twice the number of atoms as 1.0 L of Ne(g) since the molar mass of Ar is about twice that of Ne. c) a gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container d) the gas particles in a sample exert attraction for one another. e) all of the above are false.
c) a gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container
All the following are postulates of the kinetic-molecular theory of gases except: a) the collisions between molecules are elastic. b) the gas molecules are in constant motion. c) at a constant temperature, each molecule has the same kinetic energy. d) the volumes of the molecules are negligible compared with the volume of the container. e) the gas molecules are in rapid motion.
c) at a constant temperature, each molecule has the same kinetic energy.
In which flask are the molecules least polar and therefore most ideal in behavior?
c) flask C
A plastic bag is weighed and then filled successively with two gases, X and Y. The following data are gathered: Temperature: 0.0°C (273 K) Pressure: 1.00 atmosphere Mass of empty bag: 20.77 g Mass of bag filled with gas X: 24.97 g Mass of 1.12 liters of air at conditions given: 1.30 g Volume of bag: 1.12 liter Molar volume at STP: 22.4 liters The bag is emptied and refilled, successively, with gases X and Y, this time at 1 atm pressure and a temperature 30°C higher. Assume that the volume of the bag is the same as before. Which one of the following statements is wrong? a) the full bag contains fewer molecules of each gas than it did at 0.0°C b) the ratio of the density of gas Y to the density of gas X is the same as at 0.0°C c) the molar masses of the two gases are the same as they were at 0.0°C d) the mass of each gas filling the bag is now 303/273 times the mass held at 0.0°C e) the average velocity of the molecules of gas X at 30°C is higher than it was at 0.0°C
d) the mass of each gas filling the bag is now 303/273 times the mass held at 0.0°C
What is the name for the lowest layer of the atmosphere, which is most influenced by human activities?
d) troposphere
Pressure is
defined as the force per unit area
For which gas are the collisions elastic?
e) all gases the same
For which gas do the molecules have the smallest average kinetic energy?
e) all gases the same
Which gas sample has the greatest number of molecules?
e) all gases the same
What conditions of P, T and n, respectively, are most ideal?
e) low P, high T, low n
In which single flask do the molecules have the greatest mass, the greatest average velocity, and the highest kinetic energy?
e) no one flask has all these
Given a cylinder of fixed volume filled with 1 mol of argon gas, which of the following is correct? (Assume all gases obey the ideal gas law)
e) none of the above
A 142-mL sample of gas is collected over water at 22°C and 753 torr. What is the volume of the dry gas at STP? (The vapor pressure of water at 22°C = 20. torr)
e) none of these
Which of the following is the best qualitative graph of P versus molar mass of 1-g sample of different gases at constant volume and temperature?
e) none of these
Given reaction N2 + 3H2 --> 2NH3, you mix 1 mol each of nitrogen and hydrogen gases under the same conditions in a container fitted with a piston. Calculate the ratio of volumes of the container (Vfinal/Vinitial).
a) 0.67
A sample of N2 gas is contaminated with a gas (A) of unknown molar mass. The partial pressure of each gas is known to be 200. torr at 25°C. The gases are allowed to effuse through a pinhole, and it is found that gas A escapes at 4 times the rate of N2. The molar mass of gas A is:
a) 1.75 g/mol
Standard pressure for gases is
b) 1 atm
Air has an average molar mass of 29.0 g/mol. The density of air at 0.97 atm and 30.0°C is:
c) 1.13 g/L
Which of the following properties of a real gas is related to the b coefficient in the van der Waals equation? a) real gases consist of molecules or atoms that have volume. b) the average speed of the molecules of a real gas increases with temperature. c) there are attractive forces between atoms or molecules of a real gas. d) the rate of effusion of a gas is inversely proportional to the square root of the molecular weight of the gas. e) none of these.
a) real gases consist of molecules or atoms that have volume.
At a given temperature and pressure, a sample of Gas A is observed to diffuse twice as fast as a sample of a different gas, B. Based on this:
a) the molar mass of A is one fourth that of B
You carry out the reaction represented by the following balanced equation: N2(g) + 3H2(g) --> 2NH3(g) You add an equal number of moles of nitrogen and hydrogen gases in a balloon. The volume of the balloon is 1.00 L before any reaction occurs. Determine the volume of the balloon after the reaction is complete. Assume constant temperature.
b) 0.670 L
What volume of measured at STP is produced by the combustion of 6.27 g of natural gas according to the following equation? CH4(g) + 2O2(g) --> CO2 + 2H2O(g)
b) 17.5 L
A balloon has a volume of 2.32 liters at 24.0 C. The balloon is heated to 48.0 C. Calculate the new volume of the balloon.
b) 2.51 L
A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6 C. Determine the temperature at which the volume of the gas is 3.42 L.
b) 278 K
If a 17.90-g sample of a gas occupies 10.0 L at STP, what is the molar mass of the gas at 125°C?
b) 40.1 g/mol
A sample of 35.1 g of methane gas has a volume of 3.11 L at a pressure of 2.70 atm. Calculate the temperature.
b) 46.8 K
A mixture is prepared from 15.0 L of ammonia and 15.0 L chlorine measured at the same conditions; these compounds react according to the following equation: 2NH3(g) + 3Cl2(g) --> N2(g) + 6HCl(g) When the reaction is completed, what is the volume of each gas (NH3, Cl2, N2, and HCl, respectively)? Assume the final volumes are measured under identical conditions.
b) 5.00 L, 0.00 L, 5.00 L, 30.0 L
According to the postulates of the kinetic theory of gases, the average speed of the molecules of a given gas is proportional to the
b) square root of the absolute temperature
You have a certain mass of helium gas (He) oma rigid steel container. You add the same mass of neon gas (Ne) to this container. Which of the following best describes what happens? Assume the temperature is constant.
b) the pressure in the container increases but does not double
Boyle's law states that:
b) the volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature
Hydrogen and chlorine gases react to form HCl. You and a friend are on opposite sides of a long hallway, you with H2 and your friend with Cl2. You both want to form HCl in the middle of the room. Which of the following is true? a) you should release the H2 first. b) your friend should release the Cl2 first. c) you both should release the gases at the same time. d) you need to know the length of the room to answer this question. e) you need to know the temperature to answer this question.
b) your friend should release the Cl2 first.
The partial pressures of CH4, N2, and O2 in a sample of gas were found to be 135 mmHg, 508 mmHg, and 571 mmHg, respectively. Calculate the mole fraction of nitrogen.
c) 0.418
A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729 mm above the pool of mercury. What is the pressure of the atmosphere? a) 1.04 atm b) 0.719 atm c) 0.959 atm d) 456 atm e) 0.639 atm
c) 0.959 atm
Given the equation: 2KClO3(s) --> 2KCl(s) + 3O2(g) A 3.00-g sample of KClO3 is decomposed and the oxygen at 24.0°C and 0.717 atm is collected. What volume of oxygen gas will be collected assuming 100% yield?
c) 1.25 x 10^3 mL
Which statement is inconsistent with the kinetic theory of an ideal gas? a) the forces of repulsion between gas molecules are very weak or negligible. b) most of the volume occupied by a gas is empty space. c) when two gas molecules collide, they both gain kinetic energy. d) the average kinetic energy of a gas is proportional to the absolute temperature. e) gas molecules move in a straight line between collisions.
c) when two gas molecules collide, they both gain kinetic energy.
Determine the number of moles of hydrogen gas present in the sample.
d) 0.056 mol
Calculate the density of nitrogen at STP.
d) 1.25 g/L
A physics experiment is conducted at a pressure of 14.4 kPa. What is the pressure in mmHg?
d) 108 mmHg
Consider the reaction between Mg(s) and HCl(aq) to produce aqueous magnesium chloride and hydrogen gas. How many liters of hydrogen gas at STP will be produced when 12.15 g of magnesium reacts with an excess of hydrochloric acid?
d) 11.2 L
Calculate the ratio of PHe : PAr.
d) 12.2/1
A vessel with a volume of 26.9 L contains 2.80 g of nitrogen gas, 0.605 g of hydrogen gas, and 79.9 g of argon gas. At 25°C, what is the pressure in the vessel?
d) 2.18 atm
The purity of a sample containing zinc and weighing 0.312 g is determined by measuring the amount of hydrogen formed when the sample reacts with an excess of hydrochloric acid. The determination shows the sample to be 84.0% zinc. What amount of hydrogen (measured at STP) was obtained?
d) 2.41 x 10^-3 molecules
The ratio of the average velocity of particles in the first container compared to that in the second is
d) 2:1
A sample of nitrous oxide, N2O, occupies 16,500 mL at STP. What is the mass of the sample?
d) 32.4
A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO2 has a total pressure of 7.3 atm. What is the partial pressure of CO2?
d) 5.1 atm
An excess of sodium hydroxide is treated with 26.5 L of dry hydrogen chloride gas measured at STP. What is the mass of sodium chloride formed?
d) 69.1 g
Which of the following is not an assumption of the kinetic molecular theory for a gas? a) gases are made up of tiny particles in constant chaotic motion. b) gas particles are very small compared to the average distance between the particles. c) gas particles collide with the walls of their container in elastic collisions. d) the average velocity of the gas particles is directly proportional to the absolute temperature. e) all of the above are assumptions of the kinetic molecular theory.
d) the average velocity of the gas particles is directly proportional to the absolute temperature.
onsider the following gas samples: Sample A Sample B S2(g) O2(g) n = 1 mol n = 2 mol T = 800 K T = 400 K P = 0.20 atm P = 0.40 atm Which of the following statements is false? a) the volume of sample A is twice the volume of sample B. b) the average kinetic energy of the molecules in sample A is twice the average kinetic energy of the molecules in sample B. c) the fraction of molecules in sample A, having a kinetic energy greater than some high fixed value, is larger than the fraction of molecules in sample B, having kinetic energies greater than that same high fixed value. d) the mean square velocity of molecules in sample A is twice as large as the mean square velocity of molecules in sample B. e) assuming identical intermolecular forces in the two samples, sample A should be more nearly ideal than sample B.
d) the mean square velocity of molecules in sample A is twice as large as the mean square velocity of molecules in sample B.
A gas sample is heated from -20.0 C to 57.0 C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.140 atm, what is the final pressure?
e) 0.0811 atm
For a gas, which two variables are directly proportional to each other (if all other conditions remain constant)? 1. T and n 2. V and n 3. V and T
e) 2 and 3 only
A sample of gas is in 50.0 mL container at a pressure of 645 torr and a temperature of 25 C. The entire sample is heated to a temperature of 35 C and transferred to a new container whose volume is 98.7 mL. The pressure of the gas in the second container is about:
e) 338 torr
A 41.1 g sample of Ne gas exerts a certain pressure in a container of fixed volume. What mass of Ar is required to exert half the pressure at the same conditions of volume and temperature?
e) 40.7 g Ar
