IB Chemistry: Grade 12: Practical 1: Stoichiometry Quantitative Preparation of a Salt and Yield Calculation

Quantitative preparation of a salt and yield calculation

Introduction:

Copper (II) sulphate can be prepared by reacting copper (II) oxide with dilute sulphuric acid. The resulting copper (II) sulphate solution can then be crystallized, so that a quantitative analysis may be made of the product formed. This can then be compared with the theoretical amount, and % yield calculated. Copper (II) sulphate crystals are CuSO4.5H2O. Therefore, the reaction is:

CuO + H2SO4 + 4H2O ® CuSO4.5H2O

0.2 mol. 0.2 mol. 0.2 mol.

Hypothesis:

According to theory, the amount of copper sulphate produced should be 159.61g. However, I believe the amount produced will be far from this. This is because the theoretical amount can never be produced exactly, even under laboratory conditions.

Apparatus:

100ml measuring cylinder (± 0.05 cm")

100ml 2M dilute sulphuric acid

250ml beaker (x2) (± 0.05 cm")

Bunsen burner

Copper (II) oxide

Funnel

Filter papers

Scale (± 0.0005

Copper mining and sulfuric acid plant, Copperhill]...

English: Author: John Dalton; Year: 1808

English: 96% sulfuric acid

g)

Clamp stand

Method:

A measuring cylinder was taken, and used to measure 100ml of 2M dilute sulphuric acid.

The acid was transferred to a 250ml beaker, and warmed with the Bunsen burner but not allowed to boil.

Copper (II) oxide was added until in excess.

The solution was filtered while still hot, and the residue was washed off.

The resulting copper (II) sulphate solution was boiled until it had been reduced by approximately 50%.

The solution was then allowed to crystallize.

Once crystallized, the solution was filtered to separate the crystals.

The crystals were dried between fresh filter paper.

The crystals were weighed on the scale.

Results:

Amount of copper (II) oxide from experiment

Theoretical weight/g 49.94

Actual weight/g (± 0.0005 g) 38.38

Yield: (38.38 / 49.94) x 100

= 76.85%

% uncertainty = 0.0005 x 100 = 1.303 x 10^-5%

38.38

Conclusion and Evaluation:

The actual yield of...