Adapted by Nelson Nuñez-Rodriguez
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By David W. Ball
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| QUESTION | ANSWER |
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1. What is the work when 124 mL of gas contract to 72.0 mL under an external pressure of 822 torr? |
1. 5.70 J |
|
3. A 3.77 L volume of gas is exposed to an external pressure of 1.67 atm. As the gas contracts, 156 J of work are added to the gas. What is the final volume of the gas? |
3. 4.69 L |
|
5. What is the heat when 1,744 g of Hg increase in temperature by 334°C? Express your final answer in kJ. |
5. 80.97 kJ |
|
7. What is final temperature when a 45.6 g sample of Al at 87.3°C gains 188 J of heat? |
7. 91.9°C |
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9. Plants take CO2 and H2O and make glucose (C6H12O6) and O2. Write a balanced thermochemical equation for this process. Use data in Table 2.2 "Enthalpies of Formation for Various Substances". |
9. 6CO2(g) + 6H2O(ℓ) → C6H12O6(s) + 6O2(g) ΔH = 2,799 kJ |
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11. The basic reaction in the refining of aluminum is to take Al2O3(s) and turn it into Al(s) and O2(g). Write the balanced thermochemical equation for this process. Use data in Table 2.2 "Enthalpies of Formation for Various Substances". |
11. 2Al2O3(s) → 4Al(s) + 3O2(g) ΔH = 3351.4 kJ |
|
13. What mass of H2O can be heated from 22°C to 80°C in the combustion of 1 mol of CH4? You will need the balanced thermochemical equation for the combustion of CH4. Use data in Table 2.2 "Enthalpies of Formation for Various Substances". |
13. 3,668 g |
|
15. What is the enthalpy change for the unknown reaction? Pb(s) + Cl2(g) → PbCl2(s) ΔH = −359 kJ PbCl2(s) + Cl2(g) → PbCl4(ℓ) ΔH = ? Pb(s) + 2Cl2(g) → PbCl4(ℓ) ΔH = −329 kJ |
15. ΔH = 30 kJ |
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17. What is the ΔH for this reaction? The label gra means graphite, and the label dia means diamond. What does your answer mean? C(s, gra) → C(s, dia) |
17. ΔH = 1.897 kJ; the reaction is endothermic. |