Chemistry energy math

Question

Determine the amount of energy (heat) in joules required to raise the temperature of 5 kg of iron from 50 c to 37 c

Answer 1

We can solve this using the equation Q = mCΔT where the definitions of the variables are outlined belows:

Q = heat energy (joules)

m = mass (g)

C = specific heat (J/(g*ºC))

ΔT = change in heat (ºC)

The specific heat for iron is 0.45 J/(g*ºC), therefore we can plug in the numbers that we have as follows:

Q = 5000 g * 0.45 J/(g*ºC) * 13 ºC = 29,250 J

We have 5000 g of iron because we have 5 kg of iron and 1000 g = 1 kg, and we have a 13 °C change because we are going from 37 ºC to 50 ºC. If we were instead going from 50 ºC to 37 ºC, the change in temperature value would be negative, giving us a negative value for our final answer.

Final answer = 29,250 J = 29.25 kJ