Experiment 6- Chemical Reactions of Copper and Percent Yield
What is the purpose of Experiment 6?
Familiarize w/ basic lab procedures,
some chemistry of a typical transition element
and the concept of % yield.
What do most chemical syntheses involve?
the separation and purification of a desired product from unwanted contaminants.
With which reactions will you become acquainted?
Redox and metathesis
What is this experiment designed to do?
to be quantitative evaluation of your individual lab skills in
carrying out some of these operations
What will you do by means of these reactions?
Carry out several chemical transformations involving
Cu and its compounds
What will you do finally?
Recover the copper sample with maximum efficiency
What will be the chemical reactions involved? (6 total)
1. Cu + HNO3 --> Cu(NO3)2 + NO2 + H2O Redox
2. Cu(NO3)2 + NaOH --> Cu(OH)2 + 2 NaNO3
3. Cu(OH)2 --> CuO + H2O
4. CuO + H2SO4 --> CuSO4 + H2O
5. CuSO4 + Zn --> ZnSO4 + Cu
6. CuSO4 + Al --> Al2(SO4) + Cu
What does each of these reactions proceed to?
When do metathesis reactions proceed to completion?
They proceed to completion whenever one of the products is removed from the solution (like in the formation of a gas or an insoluble substance)
Which reactions proceed to completion in a metathesis reaction?
1, 2, 3
1 and 3 gas forms
2 and insoluble precipitate forms
What happens with reactions 5 and 6?
They proceed to completion b/c copper is more difficult to oxidize than either Zn or Al
What is the object of the experiment?
To recover all the copper w/ wh/ you began= test of your lab skills
How do you express % yield of copper?
as the ratio of the recovered mass to initial mass of Cu
% yield= recovered mass Cu/
initial mass Cu