How much heat is required to change 36.0 g of H₂O(l) at 100 ûC to 36.0 g of H₂O(g) at 100 ûC?

Answer;

I got 91.5 kJ. Is that what you got? Here is how I solved the problem.

Solution:

In this type of problem the best approach is to determine each of the steps along the heating curve required to effect the change;

Step 1) : H₂O(s) at -10 ûC to H₂O(s) at 0 ûC

Step 2) : H₂O(s) at 0 ûC to H₂O(l) at 0 ûC

Step3) : H₂O(l) at 0 ûC to H₂O(l) at 100 ûC

Step 4) : H₂O(l) at 100 ûC to H₂O(g) at 100 ûC

Step 5) : H₂O(g) at 100 ûC to H₂O(g) at 110 ûC

Calculations;

Step 1) :

Step 2) :

Step3) :

Step 4) :

Step 5) :

TOTAL 9.15 x 10⁴ J (91.5 kJ)