Enthalpy of Combustion Experiments

Question 1

The principle here is to use the heat released by a combustion reaction to

Answer 1

increase the heat content of water

Question 2

A typical simple calorimeter is used to measure the

Answer 2

temperature changes to the water

Question 3

step 1 Fill copper can with………..

record

Answer 3

100cm cubed

initial and final temperature

Question 4

step 2 measure and record the mass of an ………

add fuel and record…………..

Answer 4

empty spirit burner

mass

Question 5

step 3
Light the wick heat water for set time until..

Record temp of

Measure mass of water and any…………..

Answer 5

completely burned

water

remaining fuel subtract the mass of fuel finally burned

Question 6

It is important that you record the

Answer 6

starting temperature, and the final temperature in order to complete the calculations

Question 7

You must also record the starting mass of the spirit burner and the final mass of the spirit burner, so that you can

Answer 7

work out the mass of the fuel burned during the reaction

This will then be used to calculate the moles, which will be used to convert Q to an enthalpy change in your calculations

Question 8

Key points to consider

Answer 8

Not all the heat produced by the combustion reaction is transferred to the water

Some heat is lost to the surroundings

Some heat is absorbed by the calorimeter

To minimise the heat losses the copper calorimeter should not be placed too far above the flame and a lid placed over the calorimeter

Shielding can be used to reduce draughts

In this experiment the main sources of error are

Heat losses

Incomplete combustion