Question

4. When a 7.50 g sample of hydrated LiClo, is heated to drive off all the water, the anhydrous residue that remains has a mass of 4.97 g. What is the mass percent of water in the hydrate?

Answer 1

Mass percent of water present in the hydrated LiClO_​​4 can be calculated as follows, given that mass of hydrated sample ( sample which contains water) and mass of anhydrated sample ( sample in which no water content is present), so that we can find the total mass of water which was present in the hydrated sample.

Mass of hydrated sample = 7.50 g

Mass of anhydrated sample = 4.97 g

Mass of water = Mass of hydrated sample - Mass of anhydrated

= 7.50 - 4.97

= 2.53 g

Mass percent of water=Mass of water/Mass of hydrated sample × 100

= 2.53/7.50 × 100

= 33.73 %

So, mass percent of water present in the hydrated LiClO_​​4 sample is 33.73%