Ahydrate is a compound that includes water molecules within itscrystal structure. during an experiment to determine the percent bymass of water in a hydrated crystal, a student found the mass of thehydrated crystal to be 4.10 grams. after heating to constant mass, themass was 3.70 grams. what is the percent by mass of water in this crystal? (1) 90.% (3) 9.8%(2) 11% (4) 0.40%

The percentage by mass of water in the crystal would be 9.8%

Mass of hydrated crystal = 4.10 grams

Mass of crystal after heating to constant mass = 3.70 grams

The heating must have removed the water. Thus, the mass of water can be calculated by removing the mass of the crystal after heating to constant mass from the hydrated mass.

Mass of water = 4.30 - 3.70

                          = 0.4 grams

Percentage by mass of water = mass of water/mass of hydrated crystal x 100

                         = 0.4/4.10 x 100

                           = 9.76

                             ≈ 9.8

More on percentage water of hydration can be found here: