How to find which equation is correct?

 Chemist can determine the equation for a reaction by measuring the masses of reactants and products. If any of the elements or compounds are gases then their relative amounts cab be found by measuring gas volume.

The aim of the experiment described here is to find out whether it is iron (II) sulfate or iron (III) that forms when iron displaces copper metal from a solution of copper (II) sulfate. If the product is the iron (II) compound then the equation is:

Fe(s) +cuSo4(aq)                      FeSO4(aq) + Cu(s)

1 mol                                                      1 mol

If, however the product id the iron (III) compound the equation is:

2Fe(s) +3CuSO4(aq)                                                              Fe2(SO)2(aq) + 3Cu(s)

2mol                                                                                                            2 mol

METHODS

Step: 1 add about 0.6 g iron filling to an empty basin from a weighing bottle. Then weigh the bottle again.

Step: 2 slowly add a warm solution of copper (II) sulfate and stir.

Step: 3 Weigh a dry filter paper and fold it to fit a funnel. Filter the contents of the basin using purified water to wash all the displaced copper into the funnel.

Step: 4 Wash the copper on the paper-first with purified water and then with prop none.

Step: 5 open out the filter paper. Allow it to dry in a warm oven. Weigh the filter paper and its contents.

NOTE:  Always check safety before carrying out any practical procedure is necessary.

REACTING QUANTITIES AND YIELDS

 In designing a procedure for making a chemical product, chemist aim to make each reaction as efficient as possible. Chemist uses the balanced equation for the reaction to decide on the quantities of reactants to start with. They also calculate the maximum yield that can be obtained in theory from the starting materials.

One of the reactants is likely to be more expensive or scarcer than the others so it is common to add the other reagents in excess. This helps to convert as much as possible of the more valuable chemical into the desired product.

CALCULATING YIELDS

 The theoretical yield for a synthesis is the mass of products expected assuming that the reaction goes according to the balanced chemical equation. We know that for calculating the percentage yield we have,

Percentage(%) yield = Actual yield / Theoretical yield * 100