Arkansas State University Department of Chemistry and Physics

1. A sample of 0.50 moles of gas is placed in a container of volume of 2.5 L.  What is the pressure of the gas in torr if the gas is at 25^oC? P = 4.89 atm = 3719 torr

2. A sample of gas is placed in a container at 25^oC and 2 atm of pressure.  If the temperature is raised to 50^oC, what is the new pressure? P = 2.17 atm

3. At 1 atm of pressure water boils at 100^oC, if the sample was placed under 2 atm of pressure, what would be the temperature?  (This would be like a pressure cooker).
T = 746 K = 473^oC = 883^oF

4. At what temperature would water boil if the pressure is 600 torr? (Use information from problem 3:  this shows why food doesn't cook well at higher elevations)
T = 294 K = 21.5^oC = 70.7^oF

5. Calculate the volume of 40.6 g of F₂ at STP. V = 23.9 L

6. A sample of 2.0 moles of hydrogen gas is placed in a container with a volume of 10.4 L.  What is the pressure of the gas in torr if the gas is at 25^oC? P = 4.70 atm = 3576

7. The tire pressure is 32 psi.  What is the pressure in torr if 1 atm = 14.7 psi?
P = 1654 torr

8. A gas is placed in a balloon with a volume of 3.0 L at 28^oC and 900 torr.  What would be the new volume for the gas if placed under STP? V = 3.2 L

9. How many moles of gas would occupy a volume of 14 L at a  pressure of 700 torr and a temperature of 30^oC? n = 0.52 mol

10. Calculate the volume of 24.0 g of HCl at STP. V = 14.8 L

11. What is the volume of one mole of acetylene gas at STP? V =22.414 L

12. What is the volume of 0.75 mol of gas at 72^oC and 2 atm? V = 10.6 L

13. After eating beans, a student collects a sample of gas at 0.97 atm and 26^oC which occupies a volume of 3.5 L, calculate its volume at STP. V = 3.1 L

14. Ammonia (NH₃) is placed in 1.5 L flask at 25^oC.  If the pressure of the gas is 0.899 atm, what is the density? d = 0.626 g/L

15. A mixture of Ar and CO gases is collected over water at 28^oC and an atmospheric pressure of 1.05 atm.  If the partial pressure of Ar is 600 torr, what is the partial pressure of CO?  (vapor pressure of water at 28^oC is 28.3 mmHg) P_CO = 0.223 atm

16. Determine the partial pressures of each of the gases in the following mixture: 17.04 g NH₃, 40.36 g Ne and 19.00 g F₂.  The gases are at 1.5 atm of pressure.
P_NH3 = 0.428 atm; P_Ne = 0.857 atm; P_F2 = 0.2124 atm

17. Potassium chlorate decomposes under heat as follows:

 2 KClO₃ (s)  ------->   2 KCl (s)  + 3 O₂ (g)

 The oxygen gas is collected over water at 25^oC.  The volume of gas is 560 mL measured at 1 atm.  Calculate the number of grams of KClO₃ used in the reaction.  (vapor pressure of water = 0.0313 atm) n_O2 = 0.022 mol; 1.81 g KClO₃