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Enthalpy changes

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Question 25

A student set up a simple laboratory calorimeter to determine the enthalpy change of combustion of liquid hexane, C6H14\text{C}_6\text{H}_{14}C6​H14​.

Experimental Data

ParameterValue
Volume of water in the copper calorimeter200 cm3200\text{ cm}^3200 cm3
Mass of hexane burner before ignition184.352 g184.352\text{ g}184.352 g
Mass of hexane burner after extinguishing183.744 g183.744\text{ g}183.744 g
Initial temperature of water18.50 ∘C18.50\ ^\circ\text{C}18.50 ∘C
Maximum temperature of water reached47.30 ∘C47.30\ ^\circ\text{C}47.30 ∘C

Determine the enthalpy change of combustion of hexane, ΔcH(C6H14)\Delta_c H(\text{C}_6\text{H}_{14})Δc​H(C6​H14​), in kJ mol−1\text{kJ mol}^{-1}kJ mol−1.

  • Assume the density of water is 1.00 g cm−31.00\text{ g cm}^{-3}1.00 g cm−3 and its specific heat capacity, ccc, is 4.18 J g−1 K−14.18\text{ J g}^{-1}\text{ K}^{-1}4.18 J g−1 K−1.
  • Give your answer to 3 significant figures.
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Enthalpy changes Questions

  1. A Level
  2. /Chemistry
  3. /Enthalpy changes