Answer to Question #136100 in Chemistry for Angelica Reveles

Question

Calculate the heat change associated with cooling a 400g iron bar from 126C to 40C. ( Cp= .44)

Answer 1

Solution:

q = m × C × ΔT

q = m × C × (T_f - T_i),

where:

q = amount of heat energy gained or lost by substance

m = mass of sample

C = specific heat capacity (J ^oC^-1 g^-1)

T_f = final temperature

T_i = initial temperature

Thus:

q = (400 g) × (0.44 J ^oC^-1 g^-1) × (40 - 126)^oC = -15136 J = -15.14 kJ

q = -15.14 kJ

The heat change = IqI = 15.14 kJ

Answer: The heat change is 15.14 kJ.