Question

Find the percentage mass of water in the epsom salt mgso4.7h2o

Answer 1

Since 7 molecules of Water is present in Epsom salt its Mass should be--
7*18=136g

Answer 2

Answer : The percentage mass of water in the epsom salt is, 51.14 %

Solution : Given,

Mass of epsom salt, $MgSO_4.7H_2O$ = 246.36 g/mole

Mass of water = 18 g/mole

Mass of $7H_2O$ = $7\times 18=126g/mole$

Now we have to calculate the percentage mass of water in the epsom salt.

$\%\text{ mass of water}=\frac{\text{Mass of }7H_2O}{\text{Mass of epsom salt}}\times 100$

Now put all the given values in this formula, we get the percentage mass of water in the epsom salt.

$\%\text{ mass of water}=\frac{126g/mole}{246.36g/mole}\times 100=51.14\%$

Therefore, the percentage mass of water in the epsom salt is, 51.14 %