York University Chemistry Unit 3 Quantities in Chemical Reactions Test

UNIT 3 TEST – Quantities in Chemical ReactionsName: ___________________ Date: ______________ _______ / 43 =
_____________%
* Be sure that your final answers contain the correct # of sig figs and units *
1. Calculate the molar mass for the following compounds. (K/U- 6 marks)
Note: The values you get for these calculations will be used in Question # 3.
a) Mg3(PO4)2
b) (NH4)2SO4
c) BaCl2.2H2O
2. Complete the following table. (K/U-15 marks)
Mass (g)
Moles (mol)
# molecules
17.8 g of Mg3(PO4)2
# atoms
atoms of oxygen
2.75 mol of
(NH4)2SO4
atoms of nitrogen
3.02 x 1021
moleculesof
BaCl2H2O
atoms of hydrogen
3.A4.6 kg sample of an unidentified metal contains 25.02 moles. Identify the unknown metal.
(T-3 mark)
4. A compound contains 39.99% carbon, 6.73% hydrogen, and 53.28% oxygen, by mass.
a) Determine the empirical formula of this compound. (K/U-4 marks)
b) If the compound has a molar mass of 330.33g/mol, determine its molecular formula (K/U-3 mark)
5.Determine which would be the limiting reagent if you were to react 16.0g of iron with 39.0g of
sulfuric acid (see the reaction equation below). (K/U-4 marks)
6. The equation below shows the reaction between magnesium nitride and water.
Mg3N2(s) + 6 H2O(l) → 3 Mg(OH)2(s) + 2 NH3(g)
a) What mass of magnesium nitride would you need to react with excess water to produce 25 grams
of ammonia? [T-3 marks]
b) If this experiment was actually done using the masses of the two reactants that you calculated in
parts a & b, and you only obtained 16.27g of ammonia, what would the percent yield be for your
experiment? [A-3 marks]
c) List and briefly describe two reasons why the actual yield of a chemical reaction this one is always
less that the theoretical yield. (C-2 marks)
SCH 3U Stoichiometry Worksheet
1. State the mole ratio between the reactants in the following balanced equation:
4NaOH + 2F2
4NaF + 2H2O + O2
2. State the mole ratio between hydrogen chloride and water in reaction of barium
hydroxide with hydrogen chloride.
3. State the mole ratio between the reactants in the complete combustion of
butane, C4H10.
4. Zinc sulfide reacts with oxygen gas to produce zinc oxide and sulfur dioxide.
Determine the number of moles of zinc oxide produced when 2.5 mol of zinc
sulfide is combined with excess O2.
5. Consider the netralization reaction of magnesum hydroxide with hydrochloric
acid. Determine the number of moles of salt produced when 5.0 mol of
hydrochloric acid is combined with excess magnesium hydroxide.
6. Potassium chlorate decomposes to form potassium chloride and oxygen gas.
What mass of potassium chlorate is required to form 120.0 g of potassium
chloride?
7. Consider the following reaction:
AlCl3(aq) + 4NaOH(aq)
NaAlO2(aq) + 3NaCl(aq) + 2H2O(l)
How many grams of sodium chloride can be obtained from 4.46 g of AlCl 3?
8. Consider the following balanced equation:
LiAlH4 + 4H2O
LiOH + Al(OH)3 + 4H2
How many grams of Al(OH)3 will be produced from the hydration of 4.20 g of
LiAlH4?
9. Diphosphorous pentachloride reacts with water to produce phosphoric acid in a
synthesis reaction. Calculate the number of grams of phosphoric acid that will
be produced when 105.9 g of diphosphorous pentachloride are reacted.
10. Consider the double displacement reaction of silver nitrate with calcium
chloride. Calculate the number of moles of the silver-containing product that will
be produced when 135.0 g of calcium chloride are reacted.
11. Magnesium metal reacts with phosphoric acid to produce magnesium
phosphate and hydrogen gas. Calculate the number of moles of magnesium
phosphate that will be produced when 112.0 g of magnesium are reacted.
12. Iron(III) oxide can be formed by combining iron and oxygen gas. Determine the
mass of iron(III) oxide produced when 48.2 g of oxygen gas is reacted with
excess iron.
13. Lithium phosphate is reacted with zinc nitrate. Determine the mass of lithium
phosphate required to react completely with 415.0 g of zinc nitrate.
14. Lithium phosphate is reacted with zinc nitrate. Determine the mass of lithium
nitrate that will be produced when 415.0 g of zinc nitrate is combined with
excess lithium phosphate.
15. A piece of iron is placed in an aqueous solution of copper (II) nitrate. Determine
the mass of the copper that will be formed when 119.5 g of solid iron is reacted
with excess copper(II) nitrate.
16. Write the balanced chemical equation for the complete combustion of propane,
C3H8. Determine the mass of carbon dioxide that will be formed when 131.0 g of
propane, C3H8, is reacted with excess oxygen.
17. Write the balanced chemical equation for the complete combustion of methane,
CH4. Determine the mass of oxygen that will react completely with 18.3 g of
methane, CH4.