# Can you show me if i did these calculations right?

1. Jul 25, 2009

### graphicer89

1. The problem statement, all variables and given/known data

The specific heat of mercury is .03 cal/g C and its boiling point is 357 C. The specific heat of water is 1 cal/g C. It takes 65 calories of energy to vaporize one gram of mercury and 540*(edit) calories to vaporize 1 gram of water. If both substances begin at room temperature ( about 22 C) does it take more energy to boil a gram of mercury or a gram of water? Show your calculations.

Mercury Calculations:

Water calculations:

3. The attempt at a solution

I will just go straight to the trying to solve it out......

Mercury Calculations.....

1 x .03 x ( 357-22) +65 = energy required for mercury
1 x .03 x 335 + 65
1 x 10.05 + 65 =
75.05 ........did i do this right?? by your calculations???

Water Calculations:

1 x 1 x (100 -22) + 540 = energy required for water
1 x 1 x 78 + 540
78+540 =
618 = cal energy required for water.......So did i do both right ....
.....so basically it required more energy to boil a gram of water...

Last edited: Jul 25, 2009
2. Jul 25, 2009

### cepheid

Staff Emeritus
The 540 for energy of vaporization of water is not consistent with what is given in your problem (430). Aside from that, the calculations seem alright.

3. Jul 25, 2009

### graphicer89

Your completely right cepheid i messed up ....instead of 430 it should had been 540 ....but does it seem right??? now that its 540?

4. Jul 26, 2009

### cepheid

Staff Emeritus
As far as I can see, your calculations look fine. I don't see any obvious errors with the method or with the arithmetic.