(2.33B) Investigate energy content in a food sample

Detail the method of the experiment to investigate the energy content of a food sample.

1. Use the measuring cylinder and pour 25cm³ of water into a boiling tube.

2. Record the starting temperature of the water.

3. Record the mass of the food sample.

4. Burn the sample using a Bunsen Burner and hold 2cm from the boiling tube until it has fully burned.

5. Record the final temperature of the water.

6. Repeat for different food samples.

How does the water temperature affect the energy of the sample?

The higher the increase in temp, the more energy in the sample.

State the equation to calculate the energy in each sample.

Energy (J)=

(mass of water * temp increase * 4.2) / mass of food sample

Why is 4.2kJ used in the equation?

It is the specific heat capacity of water- the energy required to raise 1kg of water by 1 degree.

What could limit the investigation? How can they be fixed?

Incomplete burning of sample. (relight sample until fully burned.)

Heat energy lost to surroundings. (as long as procedure remains the same between samples, the results can still be compared.)