CHEM 1411 PRACTICE PROBLEMS Chapters 5 1. What volume (in L) does a sample of air occupy at 6.6 atm when 1.2 atm, 3.8 L of air is compressed? (a) 0.34 (b) 0.57 (c) 0.69 (d) 0.77 (e) 0.86 2. What is the final temperature (in K), under constant-pressure condition, when a sample of hydrogen gas initially at 88oC and 9.6 L is cooled until its finial volume is 3.4 L? (a) 31 (b) 68 (c) 94 (d) 128 (e) 260 3. What is the volume (in L) of 88.0 g of carbon dioxide gas at STP? (a) 44.8 (b) 53.7 (c) 62.1 (d) 74.6 (e) 83.2 4. What is the pressure of the gas (in atm) when 5.0 moles of CO gas are present in a container of 20.0 L at 27 oC? (a) 3.25 (b) 6.15 (c) 7.40 (d) 9.30 (e) 10.55 5. A gas evolved during the fermentation of glucose (wine making) has a volume of 0.78 L at 20.1 oC and 1.00 atm. What was the volume (L) of this gas at the fermentation temperature of 36.5 oC and 2.00 atm pressure? (a) 0.41 (b) 0.82 (c) 1.43 (d) 2.67 (e) 3.54 6. What is the molar mass (g/mol) of 7.10 grams of gas whose volume is 5.40 L at 741 torr and 40 oC? (a) 34.6 (b) 70.3 (c) 86.2 (d) 94.6 (e) 102.3 7. What is the density of HCl gas in grams per liter at 700 mmHg and 25 oC? (a) 0.54 (b) 1.37 (c) 2.24 (d) 2.97 (e) 3.57 8. A compound has the empirical formula as SF4. At 20 oC, 0.100 gram of the gaseous compound occupies a volume of 22.0 mL and exerts a pressure of 1.02 atm. What is the molecular formula of the gas? (a) SF4 (b) SF6 (c) S2F10 (d) S4F16 (e) S5F20 9. The combustion process for methane, major component of natural gas, is CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l) If 15.0 moles of methane are reacted, what is the volume of carbon dioxide (in L) produced at 23.0 oC and 0.985 atm? (a) 369.8 (b) 430.7 (c) 510.8 (d) 630 (e) 720 10. In alcohol fermentation, yeast converts glucose to ethanol and carbon dioxide: C6H12O6(s) 2 C2H5OH(l)) + 2 CO2(g) If 5.97 g of glucose are reacted and 1.44 L of carbon dioxide gas are collected at 293 K and 0.984 atm, what is the percent yield of the reaction? (a) 89.4 % (b) 76.3% (c) 65.9% (d) 56.2% (e) 47.6% 11. A mixture of gases contains 0.31 mol CH4, 0.25mol C2H6 and 0.29 mol C3H8. The total pressure is 1.50atm. Calculate the partial pressure of the CH4, C2H6 and C3H8 gases (a) 0.23,0.35,0.56atm (b) 0.54,0.44,0.51atm (c) 0.54,0.44,0.51atm (d) 0.54,0.44,0.51atm (e) 0.54,0.44,0.51atm 12. Nickel forms a gaseous compound of the formula Ni(CO) x. What is the value of x given the fact that under the same conditions of temperature and pressure, methane (CH4) effuses 3.3 times faster than the compound? (a) 1 (b) 2 (c) 3 (d) 4 1 (e) 5