Finding the Formula of Hydrated Zinc Sulphate

Finding the formula of Hydrated Zinc Sulphate

Results

Table of masses and probabilities

| Mass (g) | Uncertainty (g) | Test tube | 46.94 | ±0.01 | Test tube and hydrated sample | 59.94 | ±0.01 | Hydrated sample | 13.00 | ±0.02 | Test tube and anhydrous salt | 54.15 | ±0.01 | Anhydrous sample | 7.21 | ±0.02 | Mass of water | 5.79 | ±0.04 |

Calculations to find the Formula of Hydrated Zinc Sulphate

* Mr of Zinc Sulphate ZnSO4 = 65 + 32 + (16 x 4) =161

* Mass of water in 1 mole of ZnSO4 = Mr ZnSO4 x Mass of water Mass of anhydrous salt

* Mas of water in 1 mole of ZnSO4 = 161 x 5.79 = 129.29 7.21

* Moles of water in 1 mole of ZnSO4 = Mass of water in one mole of ZnSO4 Mr of H2O

* Moles of water in 1 mole of ZnSO4 = 129.29 = 7.18 18.00

% uncertainty of mass of anhydrous salt
% uncertainty of mass of anhydrous salt
Uncertainties
+
+
% uncertainty of mass of water
% uncertainty of mass of water
=
=
Uncertainty of mass of water in 1 mole of ZnSO4
Uncertainty of mass of water in 1 mole of ZnSO4

% uncertainty of mass of anhydrous salt
% uncertainty of mass of anhydrous salt
0.02 x 100 = 0.3%
7.21
0.02 x 100 = 0.3%
7.21
=
=
0.04 x 100 = 0.7%
5.79
0.04 x 100 = 0.7%
5.79
=
=
% uncertainty of mass of water
% uncertainty of mass of water

= 1.0%
= 1.0%
Uncertainty of mass of water in 1 mole of ZnSO4
Uncertainty of mass of water in 1 mole of ZnSO4

= 7.18g ± 1.0% = 7.18g ± 0.0718g
= 7.18g ± 1.0% = 7.18g ± 0.0718g
Mass of water