You need to boil 307 g of water (specific heat = 4.184) so you can make a cup of your favorite drink. If room temperature is 20.15 oC, how much heat is needed to boil the water?

Answer 1

I suppose you mean 4.184 J/g*C for sp.h. H2O.
q = mass H2O x sp.h. x (Tfinal-Tinitial)
q = 307 x 4.184 x (100-20.15).
That will give you q in joules needed to raise the temperature of the water from 20.15 to 100. I will not boil it. You will need an additional 2260 J for each grams of water actually boiled but I don't think the problem is asking for that.