A sample of a hydrate has a mass of 5.026 g. After it is heated, it has a mass of 3.492 g. What is the percentage by mass of water in the hydrate?

1. 19.40%

2. 27.92%

3. 30.52%

4. 69.48%

hydrate has a mass of 5.026 g

After it is heated, it has a mass of 3.492 g, that means the mass of water is

mH2O=5.026-3.492=1.534g

using the main formula

%H2O = (mass of water / mass of hydrate) x100 = 30.52%

the answer is 3. 30.52%