Question

A sample of hydrated magnesium sulfate has a mass of 4.052 g. After it is heated, it has a mass of 1.979 g. What is the percentage by mass of water in the hydrate?

Answer 1

m₀=4.052 g
m₁=1.979 g

m(H₂O)=m₀-m₁

w(H₂O)={m(H₂O)/m₀}×100=100(m₀-m₁)/m₀

w(H₂O)=100(4.052-1.979)/4.052=51.16%

51.16% H₂O

Answer 2

Answer : The percentage by mass of water in the hydrate sample is, 51.16%

Explanation :

First we have to calculate the mass of water.

Mass of water = Mass of hydrated magnesium sulfate - Mass of sample after heating

Mass of water = 4.052 - 1.979 = 2.073 g

Now we have to calculate the percentage by mass of water in the sample.

Formula used :

`\text{Mass} \%H_2O=\frac{\text{Mass of }H_2O}{\text{Mass of hydrated magnesium sulfate}}* 100`

Now put all the given values in this formula, we get

`\text{Mass} \%H_2O=(2.073g)/(4.052g)* 100=51.16\%`

Therefore, the percentage by mass of water in the hydrate sample is, 51.16%