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GAS LAWS REVIEW SHEET 1. A container of gas at 42oC has a volume of 100.0 L. What volume will the gas occupy at 65.0oC? (pressure is held constant) CHARLES’ LAW V = 107 L 2. A 165 L sample of gas exerts a pressure of 0.990 atm at 25.0oC. The gas is moved to a room where the pressure is 0.954 and occupies a new volume of 155 L. Calculate the temperature of the room. COMBINED GAS LAW T = 270 K = -3oC 3. Convert the following: 100.3 kPa mmHg 0.50 atm kPa 335 K oC 752 mmHg 51 kPa 62oC 4. Hydrogen gas and oxygen gas react in the clouds to produce water vapor. If the temperature in the atmosphere is 16oC and the pressure is 0.855 atm, what volume of hydrogen gas would be needed to produce 155 g of water? V = 239 L H2 5. A balloon holds 24.6 dm3 of gas at STP. Calculate the number of mol of gas in the balloon. n = 1.10 mol 6. A balloon holds 0.344 g of carbon dioxide gas. What is the balloon’s volume at STP? At 25oC & 105 kPa? VSTP = 0.175 L V = 0.184 L 7. If a 2.75 g sample of gas has a volume of 5.60 L at STP, what will the density of the gas be at 100oC and a pressure of 667 mmHg? V2 = 8.72 L D = 0.315 g/L 8. In a rigid container (volume is constant) why does the pressure increase when the temperature is increased? According to Guy-Lussac’s Law: as temperature is increased the kinetic energy of the particles increases. They move faster and have more collisions with the walls of the container, causing an increase in pressure. 9. In a flexible container, why would a change in temperature cause the balloon’s volume to change? What must be true of the pressure of the gas inside the balloon? With pressure held constant, an increase in temp will cause an increase in volume because the particles are moving faster and spread out. A decrease in temp causes the particles to move slower and not spread out as much. 10. If the temperature of a sample of gas remains constant and the volume of the container is increased, what happens to the pressure of the gas in the container? According to Boyle’s law, the pressure would decrease. 11. What will happen to a sealed bag of chips when you take them from here to Tahoe? (there is air in the bag too) Due to a decrease in pressure, the volume of the bag would expand. (Boyle’s Law) 12. What volume of CO2(g) can be produced by 25.0 g O2 at 19.8oC and 0.976 atm? C2H4(g) + 3 O2(g) 2 CO2(g) + 2 H2O(l) V = 12.8 L 13. If you have two containers of equal volume, why will the container holding 1 mole of gas exert less pressure than the container holding 2 moles of gas? The container with 2 moles of gas contains more particles which will cause more collisions with the walls of the container, causing greater pressure. 14. Given two containers at STP: one container holds 1.0 mole of nitrogen gas and the other contains 1.0 mol of hydrogen gas. What volume does each container occupy? Each occupies 22.4 L – the molar volume of ANY gas at STP. 15. How many grams of hydrogen are needed to produce 27.5 L of ammonia at 27oC and 102 kPa? (assume excess nitrogen) N2(g) + 3 H2(g) 2 NH3(g) m = 3.37 g H2 16. What determines the choice of the value of R that you should use in an ideal gas law calculation? The units of pressure. If the units of pressure are in atmospheres (atm) use R = 0.0821 If the units of pressure are in kilopascals (kPa) use R = 8.315