Question

A 2.000-g sample of a hydrated copper sulfate is heated, and the waters of hydration are removed. If the mass of the remaining salt is 1.278 g, what was the percentage of water in the original hydrate?

Use the formula %water=(mass of water/mass of hydrate)•100

-13.0%
-36.1%
-56.5%
-72.2%

Answer 1

B or 2nd option: 36.1%

Answer 2

The % of water in the original hydrate is 36.1%

Calculation
this is calculated by use of the formula % water mass of water/ mass of the hydrate x100

mass of water = mass of hydrate - mass of unhydrate

= 2.00 g - 1.278 = 0.722 grams
mass of hydrate =2.00 g

% water is therefore = 0.722g/2.00 x100= 36.1 %