Question

What is the percent by mass of water in Na2SO4 • 10H2O?

Use mc003-1.jpg.
5.59%
11.26%
44.08%
55.92%

Answer 1

The answer is 55.92%

Answer 2

Answer : The correct option is, 55.92 %

Solution : Given,

Molar mass of
`Na_2SO_4.10H_2O` = 322 g/mole

Molar mass of water = 18 g/mole

The mass of
`10H_2O` =
`10* 18=180g`

Now we have to calculate the percent by mass of water in
`Na_2SO_4.10H_2O`

Formula used :

`\text{Percent by mass of water}=\frac{\text{Mass of}10H_2O}{\text{Mass of }Na_2SO_4.10H_2O}* 100=(180g)/(322g)* 100=55.92\%`

Therefore, the percent by mass of water in
`Na_2SO_4.10H_2O` is, 55.92 %