1. You wish to heat 20 kg of water from 40°C to 80°C. How many kcal of heat are necessary to do this? To how many kJ does this correspond?

3,343.68kJ

Explanation:

Heat energy used up can be calculated using the formula:

H = mcΔt

m = mass oof the object (in kg) = 20kg

c = specific heat capacity of water = 4179.6J/kg°C

Δt change in temperature = 80-40 = 40°C

H = 20 * 4179.6 * 40

H = 3,343,680Joules

H = 3,343.68kJ