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?

Answer 1

20.9 is the answer

Step-by-step explanation:

because it only asks for the first decimal place

Answer 2

m₀=2.643 g
m₁=2.090 g

m(H₂O)=m₀-m₁

w(H₂O)=m(H₂O)/m₀=(m₀-m₁)/m₀

w(H₂O)=(2.643-2.090)/2.643=0.2092 (20.92%)

20.92%