1. calorimetry
C2.1 Thermochemistry
11 November 2018

2. Calorimetry
Calorimetry is used to measure the heat energy released or taken from the surroundings.
A calorimeter is used to reduce heat loss (e.g. a polystyrene cup)
A thermometer is used to measure any temperature change.
From the temperature and the mass of water we can determine the enthalpy change using the following equation:
q = m c T

3. What are the surroundings?
The surroundings include everywhere that is not the substance.
e.g. In the diagram below the surroundings (the places where the heat is either released or taken from) could be the air, calorimeter, water or thermometer.

4. How does calorimetry work?
A known volume of cold water is measured into the beaker/can
The starting temperature of the water is recorded
The water is heated using the flame from the burning fuel
The final temperature of the water is recorded
The spirit burner containing the fuel is weighed before and after the experiment.

5. Experimental vs. Data booklet values
Experimental values are often different to the data book values. This might be because of one of the following:
Energy lost to the surroundings (not all the heat is transferred to or from the water so some of it is lost)
Incomplete combustion (a lack of oxygen might result in this)
Conditions which are not standard (ie not 298K and 1atm pressure)
These errors can be reduced by adding a draught screen and an input of oxygen gas.

6. Specified Practicals
Read through the method in your required practical booklets.
I will demonstrate the experiment briefly and then you will need to complete it.
Key points for recording data:
Always record to the resolution of the apparatus used.
All calculations should use the same number of significant figures as your least accurate piece of apparatus.
Use a ruler and pencil where appropriate!

7. Examination questions

8. Examination question

11. Mark scheme

12. Past paper question

15. Mark scheme