# Question #440b7

##### 1 Answer

30.73 KJ.

#### Explanation:

use these equations:

also, use these values:

(KJ needed per mole of water to change solid

(KJ needed per mole of water to change liquid

Specific heat of water = 4.18 J/g*C

First, you have to find the amount of heat energy required for each step.

Step 1: **ice at -10 degrees to ice at 0 degrees**

q = (10)(2.09)(10)

q = 209 J = **.209 KJ**

Step 2: **ice at 0 degrees to water at 0 degrees**

10 g water = .556 mol water (divide my molar mass which is 18g)

q = (6.01)(.556)

q = **3.34 KJ**

Step 3: **water at 0 degrees to water at 100 degrees**

q = (10)(4.18)(100)

q = 4180 J = **4.180 KJ**

Step 4: **water at 100 degrees to steam at 100 degrees**

q = (40.7)(.556)

q = **22.63 KJ**

Step 5: **steam at 100 degrees to steam at 120 degrees**

q = (10)(1.84)(20)

q = 368 J = **.368KJ**

Now, add up all the values to get the final answer.

.209 + 3.34 + 4.180 + 22.63 + .368 = **30.73 KJ**

This is a very helpful reference graph.