1 Ricardo states that for the process of iron reacting with sulfur to produce iron (III) sulfide according to
16 Fe, + 3 588) ► Fe S3(s),
16.0 g of iron will react with 3.00 g of sulfur in the reaction to produce 8.00g of iron (III) sulfide. Is Ricardo's
reasoning correct? Explain your answer. (3 marks)
2. A magnesium compound is made up of magnesium and another element. It contains 72.2% magnesium by mass
and the rest is made up by the other element. If the molar mass of the compound is 100.95 g/mol, identify the
other element. (5 marks)
3. Sodium hydroxide is commonly called caustic soda, and is used in many household drain cleaners. It is prepared
by the reaction:
calcium hydroxide + sodium carbonate
-
sodium hydroxide + calcium carbonate
a) Write the balanced equation for the reaction. (2 marks)
b) What is the maximum mass of sodium hydroxide that could be produced from 195 g of calcium hydroxide?
(3 marks)
4. The reaction of iron (III) sulfate solution with a sodium hydroxide solution produces a precipitate of iron (III)
hydroxide and a solution of sodium sulfate.
Fe2(SO.)3 + 6 NaOH
2 Fe(OH), + 3 Na, so,
a) Which is the limiting reactant when 15.0 g of iron (III) sulfate reacts with an equal mass of sodium hydroxide?
(2 marks)
b) What is the maximum mass of iron (III) hydroxide that could be produced above? (3 marks)
5. Silica (SiO2) makes up about 95% of the earth's crust, and is also used to manufacture transistors. It reacts with
hydrofluoric acid to produce silicon tetrafluoride and water vapour.
SiO2 + 4 HF
-
SiF + 2 H2O
a) 10.5g of SiO2 is reacted with a small excess of HF. What is the theoretical yield, in grams, of H, O? (3 marks)
b) If the actual yield of water is 2.50 g, what is the percentage yield of the reaction? (1 mark)
c) Assuming the percentage yield in part (b), what mass of SiF, is actually formed? (2 marks)