What is the percent by mass of water present in 1.0 mole of caso4 times 2h20?

20.9% is water

Explanation:

To find the % water we will have to find the mass of water and divide by the mass of the entire compound which includes the water.

Ca 40.1 grams/mole + S 32.1 grams/mole + Oxygen 16.0 grams/mole x 4 + water 18.0 grams/mole x 2 = 172.2 grams/mole

Since water was

36.0

172.2

we get a decimal of 0.209059 which becomes 20.9% when rounded for significant figures