How to Calculate Heat Required to Boil Water?

[jle1092]

Water is boiled to add moisture to the air in the winter to help a congested person breathe better. Calculate the heat required to boil away .75 L of water that is initially 60 C.

I'm not sure what equation to use, I was thinking Q=mc(change in temp.)

where Q= heat energy
m= mass
c= specific heat


I know the specific heat of water is 1 cal/gC, but I am not given the mass and don't seem to have enough information to solve this problem. Any help would be appreciated

 

[gneill]

You've got the mass of water in terms of volume -- you do know the density of water, right?

The formula you have given is fine for part of the problem (raising the temperature of the water to the boiling point). But you'll need another constant to calculate the heat required to turn the water from liquid to vapor.