Chapter 5, Problem 74a
Using values from Appendix C, calculate the value of H for each of the following reactions: (a) CaO(s) + 2 HF(g) → CaF2(s) + H2O(g)
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For each of the following compounds, write a balanced thermochemical equation depicting the formation of one mole of the compound from its elements in their standard states and then look up H °f for each substance in Appendix C. (b) SO3(g)
Write balanced equations that describe the formation of the following compounds from elements in their standard states, and then look up the standard enthalpy of formation for each substance in Appendix C: (a) CH3OH(l)
Acetylene (C2H2(g)) is used for welding because oxyacetylene is the hottest burning common fuel gas. Using standard enthalpies of formation, calculate the quantity of heat produced when 10 g of acetylene is completely combusted in air under standard conditions.
Complete combustion of 1 mol of acetone (C3H6O) liberates 1790 kJ: C3H6O(l) + 4 O2(g) → 3 CO2(g) + 3 H2O(l) ΔH° = -1790 kJ Using this information together with the standard enthalpies of formation of O2(g), CO2(g), and H2O(l) from Appendix C, calculate the standard enthalpy of formation of acetone.
Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) and Ca(OH)2. From the following enthalpy of reaction data and data in Appendix C, calculate H°f for CaC2(s): CaC2(s) + 2 H2O(l) → Ca(OH2)(s) + C2H2(g) ΔH° = -127.2 kJ
Gasoline is composed primarily of hydrocarbons, including many with eight carbon atoms, called octanes. One of the cleanest–burning octanes is a compound called 2,3,4- trimethylpentane, which has the following structural formula: The complete combustion of one mole of this compound to CO2(g) and H2O(g) leads to ΔH° = -5064.9 kJ. (b) By using the information in this problem and data in Table 5.3, calculate H°f for 2,3,4-trimethylpentane.