# Solutions

**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 ^{o}C? P = 4.89 atm = 3719 torr**

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

**3. At 1 atm of pressure water boils at 100 ^{o}C, 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**

^{o}C = 883^{o}F**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 ^{o}C = 70.7^{o}F**

**5. Calculate the volume of 40.6 g of F _{2} 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 ^{o}C? 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 ^{o}C 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 ^{o}C? 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 ^{o}C and 2 atm? V = 10.6 L**

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

**14. Ammonia (NH _{3}) is placed in 1.5 L flask at 25^{o}C. 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 ^{o}C 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^{o}C 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 NH _{3}, 40.36 g Ne and 19.00 g F_{2}. 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 KClO _{3} (s) -------> 2 KCl (s) + 3 O_{2} (g)**

** The oxygen gas is collected over water at 25 ^{o}C. The volume of gas is 560 mL measured at 1 atm. Calculate the number of grams of KClO_{3} used in the reaction. (vapor pressure of water = 0.0313 atm) n_{O2} = 0.022 mol; 1.81 g KClO_{3}**