Chem 9.4 Calculating food energy

Question 1

Why is it important to repeat an investigation 3 times?

Answer 1

It reduces error and makes results more reliable.

Question 2

How do you know if a certain quantity of food or fuel has released a lot of energy?

Answer 2

The greater the temperature change, the more energy the food or fuel has released as heat.

Question 3

What is the equation for the energy transferred to the water as heat?

Answer 3

H = m * c * ΔT

H – Heat transferred
m – Mass of water
c – Specific heat capacity of the water (4.18 J/g/°C)
ΔT – Temperature change of the water

Question 4

Why might the value you get after an investigation be lower than a value from a secondary investigation?

Answer 4

The calculated value could be lower because not all the heat is transferred to the water; some escape to the surroundings or goes to the apparatus.

Question 5

What is the difference between heat and temperature?

Answer 5

Heat describes the transfer of energy between molecules, or from a hot body to a cold one, but the temperature is the measurement/degree of that hotness or coldness.

Heat is measured in Joules (J), while the temperature is measured in Celsius (°C).