Gases

Chemistry Department

Faculty of Science and Mathematics

SKU1013 Basic Chemistry 1

Exercise : Gas

1. Convert the following:

a. 0.745 atm to mmHg

b. 365 kPa to atm

c. 804 mmHg to kPa

2. A sample of sulphur hexafluoride gas occupies a volume of 5.10 L at 198°C. Assuming that the pressure remain constant, what temperature is needed to reduce the volume to 2.5 L?

3. A 93 L sample of dry air cools from 145°C to -22°C while pressure is maintained at 2.85 atm. What is the final volume?

4. A sample of Freon-12 occupies 25.5 L at 298 K and 153.3 kPa. Find its volume at STP>

5. A sample pf carbon monoxide occupies 3.65 L at 298 K and 745 torr. Find its volume at -14 °C and 367 torr.

6. A sample of chloride gas is confined in a 5.0 L container at 228 torr and 27°C. How many moles of gas are in the sample?

7. If 1.47 x 10-3 mol of argon occupies at 75.0 mL container at 26°C, what is the pressure in torr?

8. You have 207 mL of chlorine triflouride gas at 699 mmHg and 45°C. What is the mass in gram of the sample?

9. Find the density of Freon-11 (CFCl3) at 120°C and 1.5 atm.

10. How many moles of gaseous arsine(AsH) occupy 0.0400L at STP? What is the density of gaseous arsine?

11. Calculate the molar mass of gas at 388 torr and 45°C if 206 ng occupies 0.206 µL.

12. A 355 mL container holds 0.146 g of Ne and an unknown amount of Ar at 35°C and a total pressure at 626 mmHg. Calculate the number of moles or Ar present.

13. How many gram of phosphine(PH3) can form when 37.5 g of phosphorus and 83 L hydrogen gas react at STP?

P4 + H2 → PH3 (unbalanced)