A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 735 mm above the pool of mercury. What is the pressure of the atmosphere?
Answer:
2.
Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas.
In which flask do the molecules have the highest average velocity?
A.
flask A
B.
flask B
C.
flask C
D.
all are the same
E.
none
3.
The air pressure in the inner tube of a tire on a typical racing bike is held at a pressure of 115 psi. Convert this pressure to atm.
A.
0.151 atm
B.
7.83 atm
C.
1690 atm
D.
32.6 atm
E.
115 atm
4.
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 3.45 L.
A.
309 K
B.
281 K
C.
20.6 K
D.
294 K
E.
326 K
5.
Three 1.00-L flasks at 25°C and 725 torr contain the gases CH4 (flask A), CO2 (flask B), and C2H6 (flask C).
In which flask is there 0.039 mol of gas?
A.
flask A
B.
flask B
C.
flask C
D.
all
E.
none
6.
Three 1.00-L flasks at 25°C and 725 torr contain the gases CH4 (flask A), CO2 (flask B), and C2H6 (flask C).
In which single flask do the molecules have the greatest mass, the greatest average velocity, and the highest kinetic energy?
A.
flask A
B.
flask B
C.
flask C
D.
all
E.
none
7.
A sample of oxygen gas has a volume of 4.50 L at 27°C and 800.0 torr. How many oxygen molecules does it contain?
A.
1.16 ´ 1023
B.
5.8 ´ 1022
C.
2.32 ´ 1024
D.
1.16 ´ 1022
E.
none of these
8.
A 6.35-L sample of carbon monoxide is collected at 55°C and 0.892 atm. What volume will the gas occupy at 1.05 atm and 20°C?
A.
1.96 L
B.
5.46 L
C.
4.82 L
D.
6.10 L
E.
none of these
9.
Body temperature is about 308 K. On a cold day, what volume of air at 273 K must a person with a lung capacity of 2.00 L breathe in to fill the lungs?
A.
2.26 L
B.
1.77 L
C.
1.13 L
D.
3.54 L
E.
none of these
10.
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
B.
1:2
C.
2:1
D.
1:3
E.
3:1
11.
You have 26.4 g of O2 gas in a container with 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.
A.
36.3 g
B.
26.4 g
C.
18.2 g
D.
13.2 g
E.
none of these
12.
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.
13.
Which conditions of P, T, and n, respectively, are most ideal?
A.
high P, high T, high n
B.
low P, low T, low n
C.
high P, low T, high n
D.
low P, high T, high n
E.
low P, high T, low n
14.
Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure.
For which gas do the molecules have the highest average velocity?
A.
He
B.
Cl2
C.
CH4
D.
NH3
E.
all gases the same
15.
When 0.72 g of a 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?
A.
CH2
B.
C2H4
C.
C3H6
D.
C4H8
E.
none of these
16.
Gaseous C2H4 reacts with O2 according to the following equation: C2H4(g) + 3O2(g) ® 2CO2(g) + 2H2O(g) What volume of oxygen at STP is needed to react with 1.50 mol of C2H4?
A.
4.50 L
B.
33.6 L
C.
101 L
D.
67.2 L
E.
Not enough information is given to solve the problem.
17.
If a 2.15-g sample of a gas occupies 750. mL at STP, what is the molar mass of the gas at 125°C?
A.
3.07 ´ 10–2
B.
64.2
C.
70.1
D.
75.0
E.
Not enough information is given.
18.
A 3.31-g sample of lead nitrate, Pb(NO3)2, molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 1.62 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 PbO(s) takes up negligible volume.
A.
0.380 atm
B.
0.228 atm
C.
0.0342 atm
D.
1.38 atm
E.
none of these
19.
The purity of a sample containing zinc and weighing 0.198 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?
A.
0.152 L
B.
0.0330 g
C.
3.42 ´ 10–3 mole
D.
1.53 ´ 1021 molecules
E.
1.53 ´ 1021 atoms
20.
Into a 3.00-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.
20.1 atm
B.
26.1 atm
C.
10.2 atm
D.
1.68 atm
E.
none of these
21.
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 36.0 g of H2O, what volume of H2 will be produced at 273 K and a pressure of 1520 torr?
A.
22.4 L
B.
44.8 L
C.
89.6 L
D.
179 L
E.
none of these
22.
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 is the molecular formula for the compound?
A.
BH3
B.
B2H6
C.
B4H10
D.
B3H12
E.
B5H14
23.
A mixture of KCl and KClO3 weighing 1.80 grams was heated; the dry O2 generated occupied 1.40 ´ 102 mL at STP. What percent of the original mixture was KClO3, which decomposes as follows: 2KClO3(s) ® 2KCl(s) + 3O2(g)
A.
28.4%
B.
37.2%
C.
42.6%
D.
63.8%
E.
72.6%
24.
A 130.-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.)
A.
135 mL
B.
119 mL
C.
130. mL
D.
111 mL
E.
none of these
25.
A vessel with a volume of 10.0 L contains 2.80 g of nitrogen gas, 0.403 g of hydrogen gas, and 79.9 g of argon gas. At 25°C, what is the pressure in the vessel?
A.
0.471 atm
B.
6.43 atm
C.
3.20 atm
D.
5.62 atm
E.
2.38 atm
26.
Oxygen gas, generated by the reaction 2KClO3(s) ® 2KCl(s) + 3O2(g), is collected over water at 27°C in a 2.00-L vessel at a total pressure of 760. torr. (The vapor pressure of H2O at 27°C is 26.0 torr.) How many moles of KClO3 were consumed in the reaction?
A.
0.0790 moles
B.
0.119 moles
C.
0.0527 moles
D.
0.0813 moles
E.
none of these
27.
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 these are postulates of the kinetic molecular theory.
28.
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 three times the rate of N2. The molar mass of gas A is:
A.
3.11
B.
252
C.
84.0
D.
9.33
E.
none of these
29.
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 these are false.
30.
The van der Waals equation, nRT = [P + (n2a/V2)] (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
A.
the possibility of chemical reaction between molecules.
B.
the finite volume of molecules.
C.
the quantum behavior of molecules.
D.
the fact that average kinetic energy is inversely proportional to temperature.
E.
the possibility of phase changes when the temperature is decreased or the pressure is increased.
31.
Real gases deviate from ideal behavior at high temperatures and low pressures.
A.
True
B.
False
32.
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?
A.
flask A
B.
flask B
C.
flask C
D.
all are the same
E.
none
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