The specific heat capacity of a substance is the amount of energy required to raise the temperature of 1 kg of the substance by 1 degree celsius. The formula for calculating the heat is expressed as
H = mcθ
where
θ is the change in temperature(final temperature - initial temperature)
m is the mass of the substance in kg
c is the specific heat capacity
From the information given,
initial temperature = 22.3
final temperature = 31
θ = 31 - 22.3 = 8.7
m = 125g
We would convert 125g to kg
recall, 1 kg = 1000g
125g = 125/1000 = 0.125kg
c = 2.42
H = 0.125 x 2.42 x 8.7
H = 2.63J