Question

How much energy does it take to freeze 30.0g of H2O at 0 oC?

Answer 1

Energy to freeze : 10020 J

Further explanation

Given

mass of H₂O = 30 g

Required

Energy to freeze

Solution

Reaction

H₂O(l) ⇒  H₂O(s)

The heat to change the phase can be formulated :

Q = mLf (melting/freezing)

Lf = latent heat of fusion (for water/ice = 334 J/g)

Then heat to freeze :

$\tt Q= 30\times 334=10020~J$