My teacher provided info about a worksheet of problems.

Special Heat of water: 4.184
Special Heat of Steam: 2.09
Special Heat of Ice: 1.8

Based on this info, and the notes we have taken on phase changes, we are supposed to find out how much energy is needed to change certain substances.

I thought, however, that in order to create a phase change, one must use the q=m,delta,Hfusion or m,delta,Hvap. How can I perform these equations without the Hvap/fusion info provided?!

Question 4, for example asks...
...60g of water at 43 degrees celcius to steam at 140 degrees celcius.

Help please?!?!?

1 answer

q1 = heat to move T of water from 43 C to 100 = mass x speicif heat liquid water x (
Tf - Ti). Tf is final T (in this case 100 and Ti is initial T (in this case 43 C.)
Then you DO, definitely, need the delta H vap for water.
q2 = heat to evaporate water = mass x delta Hvap

q3 = heat to move T of steam from 100 C to 140 C = mass x specific heat steam x (Tf - Ti) =
The total is q1 + q2 + q3.

Judging from your post, I think you knew all of this. You will need to either look up delta Hvap or ask your teacher tomorrow. By the way, note the correct spelling of Celsius.