Question

PLEASE HELP WITH THESE TWO QUESTIONS

Answer 1

1. Q=112.8 kJ

2. Q=5.01 kJ

Further explanation

The heat required for phase change :

• melting/freezing :

Q = mLf

Lf=latent heat of fusion

• vaporization/condensation

Q = mLv

Lv=latent heat of vaporization

1.

m=50 g=0.05 kg

Lv (water) = 2256 kJ/kg

$\tt Q=0.05\times 2256=112.8~kJ$

2.

m=15 g=0.015 kg

Lf for water = 334 kj/kg

$\tt Q=0.015\times 334=5.01~kJ$