In an experiment to determine the % of water (by mass) in hydrated CuSO4, the following data was recorded:

Question

mass of evaporating dish	21.35g
mass of evap dish and hydrated CuSO4	22.35g
mass of evap dish and anhydrous CuSO4	21.99g

 

Find the % of water in the hydrate

Answer 1

The % water (by mass) will be the mass of water divided by the mass of hydrated CuSO₄ times 100%.

%H₂O = mass H₂O / mass hydrated CuSO₄ (x100%)

From the data provided, we can find the mass of anhydrous CuSO₄ and the mass of water.

mass of hydrated CuSO₄ = mass of dish & hydrated CuSO₄ - mass of dish = 22.35 g - 21.35 g = 1.00 g

mass anhydrous = mass of dish & anhydrous - mass of dish = 21.99 g - 21.35 g = 0.64 g

mass of H₂O = mass of hydrated - mass anhydrous = 1.00 g - 0.64 g = 0.36 g H2O

Percent H2O (by mass) = 0.36 g /1.00 g (x100%) = 36%