Answer:
The heat of combustion of hexane is -4324kjmol-1
Explanation:
Heat of combustion is the heat evolved when a mole of a substance is burned completely in oxygen under standard conditions.
To solve this problem, all the required values have been given.
Change in temperature ΔT = 30K
Mass of water =200cm3= 200g
Mass of Hexane burned = 0.5g
Step 1:
Find the amount of hear given off
Heat evolved= mass * specific eat capacity of water* temperature change
= 200 * 4.18 * 30
= 25080J
Step 2:
Calculate the relative molecular mass of hexane
RMM of C6H14 = 86g/mole.
Step 3:
Calculate the number of moles of Hexane burned
Numbrt of mole of hexane = mass / molar mass
n = 0.5 / 86
n = 0.0058mole
Step 4:
Calculate the enthalpy change of combustion for 1mole
Combustion of 0.0058mole hexane produces 25080J of heat energy
I mole hexane produces 25080 /0.0058
= 4324kJ of heat energy.
The enthalpy change of combustion of Hexane is -4,324kJmol-1.
There is no need to do anything else for the question.
