Practical: Energy Content of Food

Question 1

What needs to be measured to determine the energy content of food?

Answer 1

• Change in water temperature.
• Mass of food (should be the same for each sample).

Question 2

State the formula for calculating the energy value of a food sample.

Answer 2

Energy = mass of water x temperature change x 4.2

Question 3

Why should the boiling tube be at an angle?

Answer 3

So the water can be heated more evenly.

Question 4

What should be done when the flame of the burning food sample goes out?

Answer 4

Relight it and continue to heat the water until the food sample does not relight anymore.

Question 5

State 2 sources of error in this practical.

Answer 5

• Incomplete combustion of food sample.
• Heat loss to surroundings.
• Inconsistent angle of boiling tube.

Question 6

State a hazard and safety precaution involved in this practical.

Answer 6

Take care to keep hands away from burning food, dripping fat from the food sample and the Bunsen flame.