Gen Chem 1 Lab 7: Copper and Percent Yield

percent yield formula

(recovered mass/ initial mass) x 100%

reaction 1 equation

Cu(s) + 4 HNO3 (aq) —> Cu(NO3)2 (aq) + 2NO2 (g) + 2 H2O (l)

Cu(s) + 4 HNO3 (aq) —> Cu(NO3)2 (aq) + 2NO2 (g) + 2 H2O (l) visual

turned from orange to green, pungent brown gas’s formed, turned blue when water was added

reaction 2 equation

Cu(NO3)2 (aq) + NaOH (aq) —> Cu(OH)2 (s) + NaNO3 (aq)

Cu(NO3)2 (aq) + NaOH (aq) —> Cu(OH)2 (s) + NaNO3 (aq) visual

solution turned into a deep blue gel

reaction 3 equation

Cu(OH)2 (s) -heated→ CuO (s) + H2 (g)

Cu(OH)2 (s) -heated→ CuO (s) + H2 (g) visual

condensation on the beaker, mixture turned black

after reaction 3 we decanted the resulting solution twice, what were we removing ?

OH ions

reaction 4 equation

CuO (s) + H2SO4 (aq) → CuSO4 (s) + H2 (g)

reaction 4 observations

condensation on beaker

reaction 5 equation

CuSO4 (aq) + Zn (s) → Cu (s) ZnSO4 (aq)

reaction 5 observations

gas evolved

what are you removing from decanting after CuSO4 (aq) + Zn (s) → Cu (s) ZnSO4 (aq) ?

unreacted zinc

if your percent yield was more than 100%, what are two plausible errors you may have made?

The product was not sufficiently dried, or the sample was contaminated within an impurity

how do you find the limiting reagent of a reaction?

You take both reactants and how much of them there are and see how much you can make of a product

when mixture of 14 g of acetylene in 14 g of oxygen is ignited. The resultant combustion reaction produces CO2 and H2O according to the following balanced equation. What is the limiting reactant?

2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (g)

O2

how many milliliters of 5.5 M H2S04 are required to react with 0.71 g of CuO according to the equation

CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (l)

1.6 mL

If 1.80 g of Zn is allowed to react with 1.73 g of CUSO4 according to the equation CuSO4 (aq) + Zn (s) → ZnSO4 (aq) + Cu (s) , how many grams of Zn will remain after the reaction is complete?

1.09 g