Feso4 • 7h2o
what is the percent by mass of water in the hydrate?

%
what is the percent by mass of the anhydrous salt in the hydrate?
%

1. Percent by mass of H₂O = 45.3%

2. Percent by mass of anhydrous Salt (FeSO₄) = 54.7 %

Explanation:

Data Given

Formula of the Molecule = FeSO₄ • 7H₂O

% by mass water (H₂O) = ?

% by mass FeSO₄ = ?

> First of all find the atomic masses of each component in a molecule

For H₂O atomic masses are given below

H = 1 g/mol

O = 16 g/mol

> Then find the total mass of H₂O in haydrated salt

7H₂O = 7 (2x1 +1x16) g/mol

7H₂O = 7 (2+16) g/mol

7H₂O = 7 (18) g/mol

7H₂O = 126 g/mol

> find total Molar Mass of Molecule:

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 16x4] + 7(2+16)

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = 278

Now to find the mass by percent of H₂O

Formula used to find the mass by percent of a component

Percent composition of  H₂O = mass of H₂O in Molecule / molar mass of FeSO₄ • 7H₂O x 100%  

Put the values

Percent by mass of H₂O = 126 (g/mol) / 278 (g/mol) x 100%

Percent by mass of H₂O = 0.4532 x 100%

Percent by mass of H₂O = 45.3%

> First of all find the atomic masses of each component in a molecule

For anhydrus salt (FeSO₄) atomic masses are given below

Fe = 56 g/mol

S= 32 g/mol

O = 16 g/mol

> Then find the total mass of FeSO₄ in haydrated salt

FeSO₄ = (56x1 + 32 + 4x16) g/mol

FeSO₄ = ( 56 + 32 + 64) g/mol

FeSO₄ = 152 g/mol

> find total Molar Mass of Molecule:

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 16x4] + 7(2+16)

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = 278

Now to find the mass by percent of FeSO₄

Formula used to find the mass by percent of a component

Percent composition of  FeSO₄ = mass of FeSO₄ in Molecule / molar mass of FeSO₄ • 7H₂O x 100%  

Put the values

Percent by mass of FeSO₄ = 152 (g/mol) / 278 (g/mol) x 100%

Percent by mass of FeSO₄ = 0.547 x 100%  

Percent by mass of FeSO₄ = 54.7 %

the answer is 0.8m.

by: nicholas