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ENTHALPY OF COMBUSTION ΔHc
Enthalpy of Combustion: the heat energy given out when one mole of a substance burns in oxygen. Always exothermic, so ΔHc always negative
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MEASURING ENTHALPY OF COMBUSTION
Bomb Calorimeter: substance is burnt in a sealed container, heat released during the reaction goes into the water, can calculate ΔH by calculating ΔT of the water.
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MEASURING ENTHALPY OF COMBUSTION
School Lab: consists of simple set up of a spirit burner positioned below a container of water. Burn a substance under a known quantity of water. Measure the mass of the spirit burner before and after burning for a period of time. Use the change in mass to determine how many moles of substance has been burnt. Measure ΔT of the water. Calculate ΔH using equations.
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ENTHALPY OF COMBUSTION ΔHc
A spirit burner used 1.00g of methanol to raise the temperature of 100.0g water in a metal can from 25°C to 55°C. Assuming the heat capacity of water is 4.18 J.g-1.°C-1, calculate the molar enthalpy of combustion of methanol in kJ.mol-1.
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ENTHALPY OF COMBUSTION ΔHc
Ethanol was placed in a spirit burner and used to heat 200cm3 of water in a copper can. When the temperature of the water had increased by 5°C, the mass of the burner and ethanol had decreased by 0.36g. Calculate the enthalpy of combustion of ethanol.
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