# Homework Help: How much heat is required to convert ice into steam?

1. Apr 25, 2010

### theskyisgreen

1. The problem statement, all variables and given/known data
An ice cube of volume 12.1 cm3 is initially at a temperature of -18.1°C. How much heat is required to convert this ice cube into steam?
(the final answer must be in Joules)

2. Relevant equations
Q = m*c*deltaT
Q = m*Lf (latent heat of fusion)
Q = m*Lv (latent heat of vaporization)
density = m/v

3. The attempt at a solution
Since I was only given the volume of the ice cube, I decided to use density = mass/volume to find the mass of the ice cube. Since the final answer must be in joules, I used the density of 9.17 kg/cm^3 as the density, and found the mass to be 1109570.

I then plugged in that mass into
Q = (1109570) (2090 J/kg°C the c of ice) (18.1) to convert ice to water
Q = (1109570) (4180 J/kg°C the c of water) (100) to convert water to steam
Q = (1109570) (334000 J - the Lf of water)
Q = (1109570) (2200000 J - Lv of water)

I added all the Qs together and found the final answer to be 5.09e14, which is incorrect.
Finding the correct units was a bit tricky so I may have done something wrong there.
If anyone has any suggestions, please let me know.

2. Apr 25, 2010