Adapted by Nelson Nuñez-Rodriguez
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By David W. Ball
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| QUESTION | ANSWER |
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1. Define Hess’s law. |
1. If chemical equations are combined, their energy changes are also combined. |
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3. If the ΔH for C2H4 + H2 → C2H6 is −65.6 kJ, what is the ΔH for this reaction? C2H6 → C2H4 + H2 |
3. ΔH = 65.6 kJ |
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5. If the ΔH for C2H4 + H2 → C2H6 is −65.6 kJ, what is the ΔH for this reaction? 2C2H4 + 2H2 → 2C2H6 |
5. ΔH = −131.2 kJ |
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7. The ΔH for C2H4 + H2O → C2H5OH is −44 kJ. What is the ΔH for this reaction? 2C2H5OH → 2C2H4 + 2H2O |
7. ΔH = 88 kJ |
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9. Determine the ΔH for the reaction Cu + Cl2 → CuCl2 given these data: 2Cu + Cl2 → 2CuCl ΔH = −274 kJ 2CuCl + Cl2 → 2CuCl2 ΔH = −166 kJ |
9. ΔH = −220 kJ |
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11. Determine ΔH for the reaction Fe2(SO4)3 → Fe2O3 + 3SO3 given these data: 4Fe + 3O2 → 2Fe2O3 ΔH = −1,650 kJ 2S + 3O2 → 2SO3 ΔH = −792 kJ 2Fe + 3S + 6O2 → Fe2(SO4)3 ΔH = −2,583 kJ |
11. ΔH = 570 kJ |