What is the minimum amount of energy required to completely melt a 7.25-kg lead brick....?

Question

What is the minimum amount of energy required to completely melt a 7.25-kg lead brick which has a starting temperature of 18.0 °C? The melting point of lead is 328 °C. The specific heat capacity of lead is 128 J/(kg∙C°); and its latent heat of fusion is 23,200 J/kg.

1.68 × 105 J

2.88 × 105 J

4.56 × 105 J

5.96 × 105 J

7.44 × 105 J

Answer 1

E = m*(C*(T2-T1) + h)

m = mass

C = specific heat

T2 = final temperature

T1 = initial temperature

h = latent heat of fusion

Answer is 4.56 x10^5 J

Answer 2

E = m(C(T2-T1) + h)

=7.25((128*310)+h)=7.25*62880=4.56*10^5 J

Answer 3

5.96 × 105 J