Chapter 5 Practice Test Flashcards Preview

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Flashcards in Chapter 5 Practice Test Deck (25)
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1
Q

Using the barometer shown in the figure, determine the pressure in terms of atmosphere.

A

0.576 atm

2
Q

Which of the following statements about gases is not true?

A

There are strong, attractive forces between gas molecules.

3
Q

The volume occupied by a sample of gas is 5,780 cm3 of space. What is this volume in liters?

A

5.78L

4
Q

Suppose you have 2.9 L of helium at 1.0 atm of pressure. According to Boyle’s Law, at what pressure will cause the gas to expand to 3.5 L?

A

0.83 atm

5
Q

Suppose the volume of the gas at the top of a closed can of mineral water is 1.9 cm3. When the can is opened (at standard conditions), the gas expands to a volume of 6.5 cm3. Use Boyle’s Law to find the original gas pressure inside the can before the can was opened. You can assume that the temperature and amount of gas are constant.

A

3.4 atm

6
Q

A sample of gas is at an initial volume of 2.7 L and a temperature of 45°C. If the gas volume increases to 4.2 L, what will its temperature be? You can assume that the pressure remains constant.

A

490 K

7
Q

At what temperature (Kelvin) would a gas have no volume at all?

A

0 K

8
Q

Suppose that 2.3 L of gas at 35°C and 1.0 atm is expanded to 4.5 L at 42°C. What will the final pressure of the gas be?

A

0.52 atm

9
Q

An airplane takes off from the ground at 1.00 atm. There is a 2.0 L bottle in the baggage compartment. The bottle is filled with a mixture of nitrogen, oxygen, and carbon dioxide gases. From takeoff to 30,000 ft, the temperature drops from 27°C to −80°C. The plane then descends to 10,000 ft. What is the change in the pressure of the bottle from 30,000 ft to 10,000 ft if the temperature at the final altitude is −50°C?

A

0.100 atm increase

10
Q

A helium balloon with a volume of 2.4 L contains 0.10 moles of gas at 25°C and 1 atm of pressure. The balloon leaks 0.02 moles of gas until someone manages to seal the hole. What is the new volume of the balloon?

A

2 L

11
Q

In an experimental design, a sample of gas is collected over water at 25.0°C and 1 atm. The gas occupies as much volume as it “wants,” by displacing the water. The space above the water has a volume, V1, of 36.0 ml. Then more gas is bubbled through, until the new volume, V2, is 72.0 ml. The number of moles of gas in the space above the water is _______________

A

doubled.

12
Q

A poisonous gas is being transported from Texas to California. The container is 4000.0 L and 4°C. It can withstand a pressure of 100.0 atm. Which of the following is the maximum safe amount of gas to ship?

A

1.76 × 10^4 mol

13
Q

At STP (standard temperature and pressure), there are 0.0357 moles of methane gas (CH4 ) in an 8.0 × 102 mL cylinder. What is the pressure exerted by the gas in the cylinder if the temperature is raised from 273 K to 320 K?

A

1.2 atm

14
Q

Two gas tanks are linked by a connecting tube with a valve. One contains 10 L of helium at 6.7 atm of pressure. The other contains 4.2 L of nitrogen at 3.6 atm of pressure. If the valve is opened, what is the final pressure of the two tanks combined?

A

5.8 atm

15
Q

A tank of gas is found in the coldest part of the refrigerator (at “standard temperature,” 0°C = 273 K). It contains 4 moles of gas: 1 mole of oxygen and 3 moles of neon. The volume of the tank is 11.2 L. What is the partial pressure of oxygen in the tank?

A

2.0 atm

16
Q

Identify the staement which best explains why a hot air balloon rises.

A

The density of hot air is less than the density of cold air.

17
Q

At a factory near the coast (at sea level, where air pressure is 760 torr), 1.00 mole of chlorine gas, Cl2 is pumped into a steel tank in a large walk-in refrigerator, at 4.0°C. What is the density of the chlorine gas?

A

3.1 g / L

18
Q

What causes the pressure in a gas sample?

A

The gas molecules collide with the walls of the container.

19
Q

A sample of helium gas, initially at standard temperature and pressure, is compressed to a smaller volume at constant temperature. What happens to the average kinetic energy?

A

It remains constant.

20
Q

What is the root mean square speed of methane, CH4, at 25°C?

A

681 m / sec

21
Q

Which of the following statements about the graph is not correct?

A

The mass of a nitrogen particle must be larger than the mass of an oxygen particle at a given temperature.

22
Q

The ratio of the rate of effusion of gas 2 to the rate of effusion of gas 1 is 0.22. If the molar mass of gas 1 (Mgas 1 ) is 3.79 g / mol, what is the molar mass of gas 2?

A

78 g/mol

23
Q

Which of the following statements about diffusion is not correct?

A

Diffusion is a process in which a gas passes through a small, pinhole opening into a vacuum.

24
Q

At higher pressures, why is the compressibility factor of real gases higher than that of an ideal gas?

A

Repulsive intermolecular interactions increase the space between real gas molecules.

25
Q

Consider 5.0 moles of O2 in a 2.0 liter container at 300.0 K. What is the pressure calculated by the van der Waals equation of state minus the pressure predicted by the ideal gas law? The ideal gas law constant is 0.08206 [L•atm] / [mol•K]. For O2, the pressure correction constant is 1.382 [L2•atm] / [mol 2 ], and the volume correction constant is 0.03186 L / mol.

A

-4 atm

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