# How much heat is necessary to vaporize 500 g of water at its boiling point?

Nov 22, 2015

It depends on what temperature the water is starting at.

#### Explanation:

If the water is in solid form it would go through 2 phase changes. That equation is:

$q = m \Delta {H}_{f}$

The $\Delta {H}_{f}$ should be given to you or easily accessible.

However, when calculating the amount of heat necessary to heat to a certain temperature you need the initial temperature. That equation looks like this:

$q = m {C}_{s} \Delta T$

We're lacking some information in the question. Get that temperature information and we can figure it out.