3:08 practical: investigate temperature changes accompanying some of the following types of change: salts dissolving in water, neutralisation reactions, displacement reactions and combustion reactions

Initial temp. of solution (oC)	Maximium temp. of solution (oC)	Temperature rise (oC)
24.2	56.7	32.5

Note:  mass of 50 cm³ of solution is 50 g

 

EXPERIMENT2: Combustion reactions

To measure the amount of energy produced when a fuel is burnt, the fuel is burnt and the flame is used to heat up some water in a copper container

Example: ethanol is burnt in a small spirit burner

Method:

1. The initial mass of the ethanol and spirit burner is measured and recorded.
2. 100cm³ of water is transferred into a copper container and the initial temperature is measured and recorded.
3. The burner is placed under of copper container and then lit.
4. The water is stirred constantly with the thermometer until the temperature rises by, say, 30 ^oC
5. The flame is extinguished and the maximum temperature of the water is measured and recorded.
6. The burner and the remaining ethanol is reweighed. For example:

Mass of water (g)	Initial temp of water (oC)	Maximum temp of water (oC)	Temperature rise (oC)	Initial mass of spirit burner + ethanol (g)	Final mass of spirit burner + ethanol (g)	Mass of ethanol burnt (g)
100	24.2	54.2	30.0	34.46	33.68	0.78

The amount of energy produced per gram of ethanol burnt can also be calculated: