# 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 in...

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