Answer to Question #74557 in Physics for Aina fahada

Question

*A container holding 1.20 kg of water at 20.0°C is placed in a freezer that is kept at -20.0°C.
The water freezes and comes to thermal equilibrium with the interior of the freezer. What is
the minimum amount of electrical energy required by the freezer to do this if it operates
between reservoirs at temperatures of 20.0°C and -20.0°C?

Answer 1

Latent heat of fusion for water is 333kJ/kg
Specific heat capacity of water is 4180J/kg degree Celsius
Specific heat capacity of ice is 2110J/kg degree Celsius
Q = m(c_w)(t_2-t_1) + m(l) + m(c_i )(t_2f - t_1f)
Q = 1.2∙4180∙(-20) + 1.2∙330000 + 1.2∙2110∙(-20)
Q = -550560 J