Question

A sample of hydrated calcium sulfate has a mass of 2.643 g. After dehydration, the sample has a mass of 2.090 g. What is the percent by mass of water in the hydrate?

___%
A sample of hydrated iron (II) chloride has a mass of 0.385 g. After dehydration, the sample has a mass of 0.245 g. What is the percent by mass of water in the hydrate?

___%
A sample of hydrated magnesium chromate has a mass of 8.557 g. After dehydration, the sample has a mass of 5.211 g. What is the percent by mass of water in the hydrate?
___%

Answer 1

For the first one
2.643-2.090= .553
.553 is the grams of water that the hydrate had before dehydration
.533/2.643=.209
.209×100= 20.9% water

Just do the same thing for the other problems

Answer 2

20.92

36.4

39.1

Have a nice day!