A 50.0 g sample of liquid water at 0.0°c ends up as ice at -20.0°c. How much energy is involved in this change.

-4200J

Explanation:

Since q = mc∆T

where:

m = mass of the substance

c = specific heat capacity of the substance

∆T = change in temperature in Kelvin

but;

the specific heat capacity of water = 4.2J/K/g

Therefore q = 50*4.2*(253-273)

q = -4200J

Note: the negative is only used to indicate heat loss

Hope this helps

there all right good

explanation:

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.