CHEMISTRY 11
Unit 5 Assignment – Chemical Reactions
Name: Date: /132
Part A. Chemical Reactions.
Write complete balanced equations including phase subscripts and also Classify each one. (3 marks each-45 marks)
1. Lead and phosphorus powders are added and react.
2. Calcium metal reacts with fluorine gas.
3. Methane is decomposed.
4. Potassium reacts with liquid sulphur.
5. Iron (III) bromide is reacted to isolate bromine.
6. Propane C3H8 (l) is burned as a fuel.
7. A solution of lead (II) nitrate is added to the solution of sodium carbonate.
8. Magnesium is added to hydrochloric acid.
9. Iron (II) acetate solution is added to a solution of barium chloride.
10. Sulphur is obtained from gaseous sulphur trioxide.
11. Aqueous iodine is reacted with a solution of potassium chloride.
12. Iron ore (iron (III) oxide) is reacted with carbon to refine iron. Carbon dioxide gas is produced.
13. Potassium is added to water. The resulting chemical solution is basic and the gas produced “pops” with a lit splint.
14. A gas that will re-ignite a glowing splint is reacted with liquid octane C8H18.
15. A solution of nickel (III) nitrate is added to a solution of phosphoric acid.
Part B. Mole Calculations ( 2 marks each – Total 24 marks)
1. How many atoms of oxygen are there in 105.3 g of glucose?
2. What volume would 16.2 g of nitrogen gas occupy at STP?
3. How many atoms would 2.35 L of neon have?
4. If a sample of disulphur hexabromide had 6.99 x 1023 atoms of bromine what mass would the sample have?
5. Find the total number of atoms in 7.67 g of sodium phosphide.
6. How many carbon atoms in 60.5 g of ethanol?
7. How many molecules in
a) 7.56 g of bromine gas?.
b) 88.55 g of carbon monoxide gas?.
c) 18.6 L of chlorine gas (at STP)?
d) 1.56 x 103 L of methane gas at STP?
8. What volume, at STP, would
a) 6.85 x 1022 molecules of sulphur dioxide take up.
b) 68.7 g of helium take up.
Part C. Empirical and Molecular Formula/Percent Composition (2 marks each, total marks – 14 marks)
1. A sample is made of 5.87 g Ni and 10.64 g Cl. Determine the empirical formula of this compound.(2 marks)
2. A 5.38 g sample is made of 4.44 g C and the rest hydrogen. Determine the empirical formula of this compound. (2 marks)
3. A compound is made of 5.89 g cobalt, 2.80 g nitrogen and 9.60 g oxygen. Determine the empirical formula of this compound. (2 marks)
4. A sample is made of 4.30 g carbon and 0.723 g hydrogen. Determine the molecular formula of this compound if its molar mass is 168.36 g/mol. (2 marks)
5. A sample is made of 16.3 g carbon, 2.75 g hydrogen and 25.8 g fluorine. Determine the molecular formula of this compound if its molar mass is 66.06 g/mol. (2 marks)
6. Determine the % composition of copper in Cu3BO3(2 marks)
7. Determine the % composition of each atom in PbCr2O7 (2 marks)
Part D. Stoichiometry
A balanced equation reveals mole ratios, which can be converted, as needed, into information in grams, and used to solve stoichiometry problems. (2 marks each – total – 24 marks)
1. What mass of fluorine will react with 105.3 g of aluminum ?
2. What volume of carbon dioxide would be produced when 26.2g of methane gas is combusted (burned) ?
3. What mass of lithium metal is needed to react with 8.35 L of nitrogen gas ?
4. If 12.3 g of lead (II) nitrate reacts with silver bromide, what mass of silver nitrate is made ?
5. Determine the number of molecules of ammonia made when 7.65 g of hydrogen gas reacts with excess nitrogen.
6. How many moles of hydrogen gas are needed to react with 15.1 L chlorine gas to produce hydrogen chloride gas?
7. How many litres of oxygen gas are needed to react completely with 16.2 g of hydrogen gas to produce water?
8. How many moles of calcium oxide are produced when 36.4 g of calcium reacts completely with oxygen gas?
9. How many grams of aluminum are required to produce 41.70 g of aluminum oxide, through the reaction of aluminum with oxygen gas?
10. How many grams of solid iodine are produced by the decomposition of 2.54 x 1024 molecules of hydrogen iodide gas?
11. How much energy is released when 235.6 g of Na metal reacts with chlorine gas?
2 Na + Cl2 2 NaCl ∆H = -36.5 kJ
12. How energy will be required to complete the reaction of 12.2 g of sodium to produce sodium oxide?
4 Na + O2 + 124.7 kJ 2 Na2O
Part E. Limiting Reactant And Percent Yield (total marks-34)
A substance that is not present in sufficient quantities to react with all of another substance present is called a limiting reactant; the other substance is said to be in excess.
1. In the reaction 2 H2 + O2 2 H2O, exactly 8.51 g H2 is combined with 9.25 g O2 and a reaction occurs. Determine the
a) limiting reactant: (2 marks)
b) amount of the product in moles. (2 marks)
2. If 0.143 g K and 0.236 g Cl2 are reacted in the reaction 2 K + Cl2 2 KCl, determine the:
a) limiting reactant: (2 marks)
b) mass of the product in grams. (2 marks)
3. In the reaction of 7.45 g N2 and 4.20 g O2 to form dinitrogen monoxide, determine the
a) limiting reactant (2 marks)
b) mass of excess reactant (2 marks)
c) mass of dinitrogen monoxide produced (2 marks)
4. If 80.0 g of bromine is added to 40.0 g of sodium,
a) what is the limiting reactant? (2 marks)
b) what is the excess mass of the reactant? (2 marks)
c) what is the mass of product? (2 marks)
5. If 72.5 g of copper is reacted with 30.0 L of chlorine gas, determine the
a) limiting reactant? (2 marks)
b) excess mass of the reactant? (2 marks)
c) mass of product (CuCl2)? (2 marks)
6. Answer the following questions based on this reaction:
Pb(NO3)2 (aq) + 2 NaCl (aq) PbCl2 (s) + 2 NaNO3 (aq)
a) If 225 mL of 12.95 M Pb(NO3)2(aq) are reacted with a solution made with 5.05 g of NaCl (aq), how many grams of lead (II) chloride will be precipitated? (2 marks)
b) If the actual yield of lead (II) chloride is 1.06 g, what is the percent yield? (2 marks)
7. Ca + Cl2 CaCl2
1.00 mole of Ca and 1.00 mole of Cl2 were present as reactants. Only 106 g of CaCl2 is produced. What is the percent yield? (2 marks)
8. N2 + 3 H2 2 NH3
Exactly 0.600 mole of N2 and 1.80 mole of H2 were reacted (i.e. no excess reactant). Only 14.5 g of NH3 is produced. What is the percent yield? (2 marks)