Name:
Chemistry 11
Block:
Date:
Copper Cycle Stoichiometry
Assignment
1) Consider the reaction below, which is the first step in the process of recycling copper.
Cu(s) + 4HNO3(aq) Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)
a) If a student began the experiment with 0.020g of copper metal, what volume (in mL) of
concentrated (15.8M) HNO3 would be required to complete the reaction?
b) How many milliliters of NO2 gas would be produced if the reaction was carried out at
STP?
c) How much Cu(NO3)2 (in grams) would be produced?
2) The next step in the process follows the reaction below:
Cu(NO3)2(aq) + 2NaOH(aq) Cu(OH)2(s) + 2NaNO3(aq)
a) If all of the Cu(NO3)2 produced in question 1 was used, what would be the mass of the
precipitate produced in the reaction above?
b) How many grams of NaNO3 would be produced?
c) How much base (mL of 0.10M NaOH) would be needed in order to have a complete
reaction?
3) The solid copper(II) hydroxide decomposes in heat to form Copper(II) oxide and steam
according to the reaction below:
Cu(OH)2(s) + heat CuO(s) + H2O(g)
What mass of solid CuO would result if the reaction went to completion?
4) When reacted with sulphuric acid, H2SO4, the reaction follows the following equation:
CuO(s) + H2SO4(aq) CuSO4(aq) + H2O(l)
a) Knowing that the density of water is 1.0g/cm3, what volume of water would be produced
in this process?
b) What volume in millilitres of 6.0M sulphuric acid would be needed to fully react with the
CuO produced in question 3?
c) What mass of copper(II) sulphate, CuSO4(aq), would be in solution at the end of the
reaction?
5) In the final step of the process, solid copper metal is reformed using magnesium metal,
according to the following reaction:
CuSO4(aq) + Mg(s) Cu(s) + MgSO4(aq)
a) What mass of MgSO4 would be produced in this reaction?
b) What is the minimum mass of magnesium metal that could be used in this reaction?
c) What should the final mass of copper metal be? How does this mass compare to the
starting mass of copper metal in step 1?
6) To remove any excess magnesium, sulphuric acid is added to the system described in part
5, which produces hydrogen gas and additional magnesium sulphate according to the
reaction below:
Mg(s) + H2SO4(aq) H2(g) + MgSO4(aq) + 89.4kJ
a) If 0.0400g of magnesium were used, what mass of magnesium would be left over to be
removed by the sulphuric acid?
b) What volume, in millilitres, of the 6.0M sulphuric acid would be required to remove this
mass of magnesium?
c) What volume of hydrogen gas would be produced at STP?
d) What would be the total mass of MgSO4 found in the reaction container after the
reactions in 5 and 6 were both complete?
e) How much energy (in kJ) will be released during the reaction (hint: start with the mass of
magnesium that is reacting – you found it in part a)