Confused earth science

Question

How many calories does it take to heat 10 grams of 9 degree C water to a vapor?

Answer 1

This should be done in 2 steps.  First, heat the water to its boiling point of 100°C.  Look up the specific heat of water, c, in the appropriate units.

 

Q₁ = mc(100 - 9)°C

 

m =  mass of the water (given)

 

That is the first heat transfer.  For the second heat transfer, look up the latent heat of vaporization of water, l_v.  This heat transfer occurs at a constant temperature of 100°C, which is the boiling point of water.

 

Q₂ = ml_v

 

The total heat required is

 

Q = Q₁ + Q₂ = mc(100 - 9)°C + ml_v

 

You should be able to find the specific heat and latent heat of vaporization in a basic chemistry book.  Be careful with units!