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Worksheet 22 . Topic 6

Set B: Percent composition of hydrate Objective: To test your ability to calculate percent
of water in hydrates
For each hydrate below, calculate percent by mass of water.
Total mass of H2O

Set up using equation: % H2O = Formula mass of hydrate x 100
Then calculate % water. show set up here Write answers here
5. CaCl2. 2H2O % H2O =

6. Na2CO3.10H2O % H2O =
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7. Al(ClO3)3.6H2O % H2O =

For each lab information provided below, calculate the percent of water in the hydrate.
For each: Determine the mass of water, set-up the problem with equation, and solve.

8. A student heated a 10.5 grams of a hydrate until all water of hydration is driven off. The student
determined the mass of the anhydrous to be 7.2 grams. What is the percent of water in the hydrate?

Mass of water = % water =
Need help? Study Book pg 128 - 129 Set 11 - 12

9. In a laboratory procedure, a student heated a 6.3 g of a hydrate salt to remove all water of hydration.

The anhydrous remaining has a mass of 3.8 grams. What is the percent of water in the hydrate?

Mass of water = % of water =

10. The data below was collected from a laboratory procedure to determine percent of water in a hydrate.
Mass of evaporated dish + cover ……………………………………. 26.0 g
Mass of hydrate + evaporated dish + cover …………………… 31.0 g
Mass of anhydrous + evaporate dish + cover ……………….. 28.9 g

What is the percent by mass of water in the hydrate?
Mass of water = % water =

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