Unit 5 Thermodynamics

5.3 Exercises

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Section 5.3 Exercises

  1. Refer to Section 5.2 Exercise 6 to calculate the enthalpy of solution (ΔH for the dissolution) per mole of CaCl2.
  2. How much heat is produced by burning 4.00 moles of acetylene under standard state conditions?
  3. How many moles of isooctane must be burned to produce 100 kJ of heat under standard state conditions?
  4. When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?
  5. Does the standard enthalpy of formation of H2O(g) differ from ΔH° for the reaction [latex]2\text{H}_2(g) + \text{O}_2(g) \longrightarrow 2\text{H}_2 \text{O}(g)[/latex]?
  6. How many kilojoules of heat will be released when exactly 1 mole of manganese, Mn, is burned to form Mn3O4(s) at standard state conditions?

Solutions

  1. −81 kJ mol−1
  2. 5204.4 kJ
  3. 1.83 × 10−2 mol
  4. 802 kJ mol−1
  5. Yes, the standard enthalpy of formation of H2O(g) is equal to ΔH° for the reaction [latex]\text{H}_2(g) + \frac{1}{2}\text{O}_2(g) \longrightarrow \text{H}_2 \text{O}(g)[/latex]?
  6. 459.6 kJ

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