3Percent Composition of Hydrates 2017.notebook
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DO NOW
What is the percent composition of lithium in Li2CO3 ?
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Percent Composition of a Hydrate
Aim: To calculate the percent composition by mass of water in a hydrate
3Percent Composition of Hydrates 2017.notebook
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January 18, 2017
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What is a hydrate?
Hydrate A salt compound that contains water molecules within it's structure.
Hydrate formulas:
CuSO4●5 H2O
FeCl3● 6 H2O
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Heating a Hydrate
• When a hydrate is heated, the water molecules evaporate
• The hydrate is now called an anhydrous salt it no longer contains water.
• mass of water= mass of hydrate mass of anhydrous salt
What information do we need to find the mass of the water?
3Percent Composition of Hydrates 2017.notebook
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Water in a Hydrate by Heating1. The initial weight of a hydrate is 5.06 grams. After heating, the final weight of the anhydrate is 4.50 grams. Determine the percent composition of water in the hydrate.
Water in a Hydrate by Formula Analysis2. What is the percent by mass of water in FeCl3●6 H2O?
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Percent of water in a Hydrate using GFM
4. What is the percent composition of water in the hydrate, CuSO4 ● 5 H2O?
3. What is the percent composition of water in the hydrate, CaCl2 ● 4H2O?
3Percent Composition of Hydrates 2017.notebook
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PRACTICE HYDRATE PROBLEMS
1. Calculate the percent water in a hydrate using the following information:
Mass of hydrate: 93.0gMass of anhydrous compound: 71.3g
2. A student heats a hydrate until the mass remains constant. The student records the following data:
Mass of the hydrate before heating = 4.65 gramsMass of the hydrate after heating = 3.09 grams
What was the percent by mass of the water in the hydrate before heating?
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PRACTICE HYDRATE PROBLEMS
3. What is the percent composition of water in the hydrate, MnCl7 ● 4H2O ?
4. What is the percent composition of water in the hydrate, Ba(ClO3)2 ● 7 H2O ?
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