Gases Test Corrections

During a laboratory experiment, a student filled a balloon with two different gases, CO₂ and N₂. The atmospheric pressure in the laboratory was 103 kPa. The partial pressure of the CO₂ added to the balloon was 40 kPa. What was the partial pressure of the N₂ in the balloon?

• A. 43 kPa

• B. 53 kPa

• C. 63 kPa

• D. 73 kPa

Which of the following statements are a postulate of the kinetic molecular theory?

• The particles of a gas do not move.

• The amount of kinetic energy within a gas is dependent on the temperature of the gas.

• The collisions between gas particles are elastic.

• The number of particles of a gas determines the volume of a gas.

• Gas particles will move in a straight line until they collide with another particle of the walls of the container.

A sample of oxygen with a volume of 2 L is compressed to a volume of 1 L. Based on the kinetic theory of gases, how will the number of collisions and the pressure change when the volume of the gas is decreased?

• The number of collisions and the pressure will both decrease.

• The number of collisions decreases and the pressure increases.

• The number of collisions and the pressure both increase.

• The number of collisions increases and the pressure decreases.

What is true about 1 mole of any gas at STP? Select all that apply.

• It has a molarity of 0.0446 mol/L

• It has a volume of 22.4 L

• It has a mass of 28.97 g.

A scuba diving tank at a pressure of 180 atmospheres contains a mixture of three gases: oxygen, helium, and nitrogen. The partial pressures of the oxygen is 58 atm and helium is 81 atmospheres, respectively. What is the partial pressure of nitrogen in the tank?

• 0.8 atmospheres

• 22 atmospheres

• 41 atmospheres

• 319 atmospheres

A bag of chips is sitting in a room at a temperature of 25°C. The volume of the bag is 0.50 L. Estimate the volume of the bag of chips after it has been left outside in the sun at 32°C, at constant pressure.

• 0.39 L

• 0.49 L

• 0.51 L

• 0.64 L

A fire extinguisher contains 125 mol of compressed carbon dioxide. What is the volume of the gas at a temperature of 27°C and a pressure of 1 atm?

• 30.8 L

• 277 L

• 2800 L

• 3080 L

How many moles of helium would you find in a birthday balloon that had a volume of 6.2 L? Assume conditions are at STP.

• 0.28 moles

• 3.6 moles

• 12 moles

• 22.4 moles

The kinetic molecular theory helps to explain the behavior of gases. Which of the following accurately explains a postulate of the KMT based on physical phenomena?

• Gas particles have insignificant attraction to each other, which is based partly on observations that gases spread out to fill their containers.

• Gas particles are close together but can move past one another, which is based partly on observations that gases flow.

• Gas particles are large and can change shape, which is based partly on observations that the volume of gases depend on pressure.

• All of the above.

If a sealed Ziploc bag contains 0.54 L of nitrogen gas at 14°C, what would the new temperature be if the volume within the bag were decreased to 0.33 L?

• 273 K

• 277.7 K

• 195.9 K

• 175.4 K