Chemistry 5070 · O Level · Exothermic and endothermic reactions

Exothermic and endothermic reactions — practice question

The enthalpy changes for the complete combustion of methane, butane and octane in oxygen are given below. methane, $\text{CH}_4$: $-890\ \text{kJ/mol}$ butane, $\text{C}_4\text{H}_{10}$: $-2877\ \text{kJ/mol}$ octane, $\text{C}_8\text{H}_{18}$: $-5512\ \text{kJ/mol}$ What are the enthalpy changes when propane and pentane are burned completely in oxygen?

  • Apropane, $\text{C}_3\text{H}_8$: $-2220\ \text{kJ/mol}$; pentane, $\text{C}_5\text{H}_{12}$: $-4210\ \text{kJ/mol}$
  • Bpropane, $\text{C}_3\text{H}_8$: $-2220\ \text{kJ/mol}$; pentane, $\text{C}_5\text{H}_{12}$: $-3530\ \text{kJ/mol}$
  • Cpropane, $\text{C}_3\text{H}_8$: $-1560\ \text{kJ/mol}$; pentane, $\text{C}_5\text{H}_{12}$: $-4210\ \text{kJ/mol}$
  • Dpropane, $\text{C}_3\text{H}_8$: $-1560\ \text{kJ/mol}$; pentane, $\text{C}_5\text{H}_{12}$: $-3530\ \text{kJ/mol}$

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