Chapter 5 Homework Flashcards
The pressure inside a soda bottle just before it is opened is about 4.5 atm. What is this pressure in torr?
3,400 torr
Using Boyle’s Law, predict what will happen to the pressure of a gas in a container at constant temperature, if the volume of the container is changed to one-half its original size.
The pressure will increase to twice its original value
Suppose you have filled a 35.0 L car tire with air at a pressure of 40.0 lb / in2. If you attach a balloon to the tire and let the air out of the tire into the balloon until the pressure is 14.7 lb / in2, what is the final volume to which the balloon will expand, assuming that the temperature is constant and that the volume of the tire remains constant. (Hint: first calculate the final volume of the tire and the balloon, combined.)
60.2 L
An air-filled cushion has a volume of 9,783 cm^3 at a pressure of 1.04 atm. If you press on the cushion and increase the pressure to 1.37 atm, by what amount have you decreased the volume?
2,360 cm^3
Suppose that you have a 2.0 L sample of hydrogen at 1.00 atm and 59°C. If you heat the sample to 84°C and it expands to a volume of 3.7 L, what will the final pressure be?
0.58 atm
Suppose that a sample of gas is warmed while a the same time, the sample is compressed. What happens to the pressure exerted by a gas?
The pressure will definitely go up
An automotive manufacturer wants to design a new air bag, using sodium azide and ferric oxide. Its total volume when inflated will be 24.4 L at 25°C. Its pressure when inflated will be 3.0 atm. How much of each chemical should the air bag contain?
6NaN3(s) + Fe2O3(s) → 3Na2O(s) + 2Fe(s) + 9N2(g)
2 moles of sodium azide, 1/3 mole of ferric oxide
A helium balloon at 25°C, 1 atm, contains 0.30 mol of He with a volume of 7.20 L. Some helium is released, and the balloon is sealed again when it contains 0.12 mol. What is the new volume of the balloon?
2.9 L
By the kinetic-molecular theory of gases, which of the following is affected by the number of gas molecules present?
frequency of collisions
When bread is baked, CO2 gas is produced by the yeast. Which statement best explains why bread rises?
An increase in the temperature and number of moles of CO2 increases the volume of the CO2 gas which result in the rising of the bread.
Two gas tanks are linked by a connecting tube of negligible volume with a valve. One contains 15.0 L of nitrogen at 7.0 atm of pressure. The other contains 8.4 L of neon at an unknown pressure. When the valve is opened, the final pressure of the two tanks combined is 10.0 atm. What was the original pressure of neon in the one tank?
15 atm
A sample of hydrogen gas is collected over water at 23.0°C, from the reaction
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g).
The volume of the gas is 45.0 mL. The pressure of gas in the space above the water is 745.1 torr. How many moles of hydrogen PH2O = 21.1 torr at 23 C were formed?
1.77 × 10^−3 mol
What is the density of a sample of 1.00 mole of chlorine gas, Cl2 is in a steel tank at 40.0°C and 660.0 torr?
2.40 g / L
An oxygen cylinder is left in a room at constant temperature and by mistake the valve is left open, allowing some of the oxygen to leak out. What happens to the average kinetic energy and the pressure of the oxygen molecules that remains in the cylinder (assuming the temperature does not change)?
Pressure decreases but average kinetic energy does not.
An unknown noble gas has a rate of effusion that is 2.03 times slower than that of oxygen gas, O2, under the same conditions. Which gas is it?
Xe
