Calculate the percent by mass of water in the hydrated calcium sulfate salt?

Answer 1

Take the mass of the water lost and divide that number by the mass of hydrated calcium sulftate. Then multiply your answer by 100. For example:

To find the amount of water, subtract the mass of the anhydrous sample from the hydated one like this:

Mass of hydrated salt: 21.626

Mass of anhydrous salt: 21.441

21.626 - 21.441 = 0.185 (amount of water)

To find the percentage of water, divide the water mass by the hydrated mass number:

.185/21.626 = 0.00855

Now all you need to do is multiply your answer by 100 to get the percentage:

0.00855(100) = .8554%

To see this last part algebraically, you can say, "what percent of the hydrated salt (21.626) is the mass of water (0.185)?"

This would look like: x%(21.626)=0.185

Answer 2

Well, you didn't give us a compound. So that compounds the question from the start. I will use an example though, magnesium chloride.

Magnesium Chloride, MgCl2

Mass of the element you wish to find the mass percent for

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(Mass of element a x # of atoms present) + (Mass of element b x # of atoms present)

Therefore, 24.305 / (24.305) + (35.45 x 2) = 24.305 / 95.2 = 25.5% Mg by mass

Answer 3

To calculate the percent by mass of water in a hydrated calcium sulfate salt, you need to find the molar mass of water (H2O) and the molar mass of the whole hydrated compound. Then divide the molar mass of water by the molar mass of the compound and multiply by 100 to get the percentage.