Answer:
Value of X is 7
Explanation:
We are given;
- Mass of the Hydrated sample as 40.14 g
- Mass of the anhydrous salt as 22.14 g (Missing in the question)
We are required to determine the value of X in the hydrated sample, NiSO4•XH2O .
- First, we determine the mass of the anhydrous salt
- Mass of water of crystallization = Mass hydrate sample - Mass of anhydrous sample
= 40.14 g - 22.14 g
= 18.0 g
We can determine the value of X by determine simple number ratio of anhydrous compound and water molecules.
- Determine the number of moles
- Molar mass of NiSO₄ = 154.75 g/mol
- Moles of NiSO₄ = 22.14 g ÷ 154.75 g/mol
= 0.1431 mole
Molar mass of water = 18.02 g/mol
Moles of water = 18.0 g ÷ 18.02 g/mol
= 1.00 mole
We can then determine the mole ratio.
Mole ratio = 0.1431 mole : 1.00 mole
= 0.1431 mole/0.1431 mole : 1.00 mole/0.1421 mole
= 1 : 7.03
= 1 : 7
Therefore, the formula of the hydrated salt is NiSO₄•7H₂O
Thus, the value of X is 7
