Question

Consider the hydrate FeSO₄ • 7H₂O.What is the molar mass of this hydrate?

Answer 1

The molar mass of the hydrate FeSO₄ • 7H₂O is calculated by adding the molar mass of iron(II) sulfate to the total molar mass of the seven water molecules, yielding 278.015 g/mol.

Step-by-step explanation:

To determine the molar mass of the hydrate FeSO4 • 7H2O, we need to add together the molar masses of iron(II) sulfate (FeSO4) and the seven water molecules (7H2O). The molar mass of FeSO4 is made up of the molar masses of Fe (55.845 g/mol), S (32.065 g/mol), and four O atoms (4 × 15.999 g/mol). The molar mass of one water molecule is 18.015 g/mol, and since there are seven water molecules, we multiply this by 7. Adding these values together gives us the total molar mass of the hydrate.

Calculation Steps:

1. Calculate the molar mass of FeSO4:
   Fe: 55.845 g/mol +
   S: 32.065 g/mol +
   O (4 × 15.999 g/mol) = 151.91 g/mol
2. Calculate the molar mass of 7H2O:
   7 × 18.015 g/mol = 126.105 g/mol
3. Add the molar masses of FeSO4 and 7H2O to find the molar mass of the hydrate:
   151.91 g/mol + 126.105 g/mol = 278.015 g/mol

The molar mass of the hydrate FeSO4 • 7H2O is therefore 278.015 g/mol.