Chemical Reactions and Stoichiometry
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CHEMISTRY 11 REVIEW VII.1 Chemical Reactions and Stoichiometry
1. Be familiar with the following terms: chemical reaction equation, reactants, products, coefficients, system, closed system, open system, law of conservation of mass, balanced equation, diatomic molecules, precipitate, aqueous, synthesis, decomposition, single replacement, double replacement, combustion, neutralization, exothermic, endothermic, enthalpy, stoichiometry, titration, equivalence point, limiting reactant, excess reactant, percentage yield.
2. Why must chemical equations be balanced?
3. How can we tell that a chemical equation is balanced?
4. Balance the following chemical reaction equations.
(a) ___ Fe2O3 + ___ C ___ Fe + ___ CO2
(b) ___ C4H10 + ___ O2 ___ CO2 + ___ H2O
(c) ___ P4O10 + ___ H2O ___ H3PO4
(d) ___ Fe2O3 + ___ H2 ___ Fe + ___ H2O
(e) ___ C9H20 + ___ O2 ___ CO2 + ___ H2O
(f) ___ (NH4)3PO4 + ___ NaOH ___ Na3PO4 + ___ NH3 + ___ H2O
(g) ___ TiO2 + ___ B4C + ___ C ___ TiB3 + ___ CO
(h) ___ SiF4 + ___ NaOH ___ Na4SiO4 + ___ NaF + ___ H2O
(i) ___ Sn + ___ H2SO4 ___ Sn(SO4)2 + ___ SO2 + ___ H2O
(j) ___ K + ___ KNO3 ___ N2 + ___ K2O
5. List the 9 diatomic and polyatomic elements.
6. Translate the following word equations into chemical symbols and balance the resulting equations.
(a) Aluminum oxide + sulphuric acid aluminum sulphate + water
(b) Ammonium phosphate + sodium hydroxide sodium phosphate + ammonia + water
(c) Nonane (C9H20) + oxygen carbon dioxide + water
(d) Sulphur + oxygen sulphur trioxide
CHEMICAL REACTIONS AND STOICHIOMETRY 1 CHEMISTRY 11 REVIEW VII.1
7. In each of the following write a balanced equation, including phases.
(a) Nitrogen trioxide gas and hydrogen gas react to form nitrogen gas and gaseous hydrogen fluroide.
(b) Gaseous boron trichloride reacts with steam to yield solid boron trihydroxide and hydrogen chloride.
(c) Sodium nitrate crystals and solid sodium metal react to form solid sodium oxide and nitrogen gas.
8. Classify the following reactions.
(a) CuI2 + Fe FeI2 + Cu
(b) 2Sb + 3Br2 2SbBr3
(c) 2NaCl + H2SO4 2HCl + Na2SO4
(d) 4C3H7S + 21O2 12CO2 + 14H2O + 4SO2
(e) 3HCl + Al(OH)3 AlCl3 + 3H2O
(f) H2CO3 H2O + CO2
9. Complete and balance the following reactions.
(a) C3H6OS2 + O2
(b) H4P2O7 + KOH
(c) N2O
(d) HNO3 + Sr(OH)2
(e) Li + S8
(f) Mg + CuSO4
10. In an exothermic reaction, do the reactants or the products contain more energy?
11. Draw an energy diagram for a reaction having ∆ H = -35 kJ.
12. ∆H = +40 kJ for the reaction: A B. Rewrite this equation to show the 40 kJ properly on the reactant or product side.
CHEMICAL REACTIONS AND STOICHIOMETRY 2 CHEMISTRY 11 REVIEW VII.1
13. Indicate if the following represent exothermic or endothermic reactions.
+ - (a) KClO3 + 41.4 kJ K + ClO3
(b) Product
125 kJ
Energy Reactant
Reaction proceeding
(c) C12H22O11 + 12O2 12CO2 + 11H2O + 5638 kJ
(d) N2 + 3H2 2NH3 ∆ H = -78 kJ
(e) 2HCl H2 + Cl2 ∆ H = + 432 kJ (f) Reactant
75 kJ
Product Energy
Reaction proceeding
14. Consider the reaction: 4C4H9SO2 + 25O2 16CO2 + 18H2O + 4SO2
(a) How many oxygen molecules react with 20 molecules of C4H9SO2?
(b) How many water molecules will be produced when 75 molecules of O2 are reacted?
(c) When 63.5 moles of CO2 are produced, how many moles of SO2 are also produced?
(d) How many moles of C4H9SO2 are required to produce 100 moles of water?
CHEMICAL REACTIONS AND STOICHIOMETRY 3 CHEMISTRY 11 REVIEW VII.1
15. Consider the reaction: 3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 2NO(g) + 4H2O(l)
(a) What mass of H2O will be produced from the reaction of 50.0 g of Cu?
(b) What volume of 0.750 M HNO3 will be required to completely react with 15.0 g of Cu?
(c) What volume of NO(g) at STP will be formed when 250 mL of 0.500 M HNO3 reacts with excess Cu?
(d) What volume of NO(g) at STP will be formed when 20.0 g of Cu completely reacts?
(e) What is the concentration of the HNO3(aq) if 500.0 mL completely reacts with 10.0 g of Cu?
16. A 10.0 mL sample of Al(OH)3 is titrated with 37.8 mL of 0.500 M HCl according to the reaction
Al(OH)3 + 3HCl AlCl3 + 3H2O
What is the concentration of the original Al(OH)3 solution?
17. A 15.0 mL sample of a saturated solution of Ca(OH)2 is titrated with 22.7 mL of 0.0145 M HCl. according to the reaction
Ca(OH)2 + 2HCl CaCl2 + 2H2O
(a) What is the molarity of the Ca(OH)2 in solution?
(b) What mass of Ca(OH)2 is dissolved in 250.0 mL of saturated Ca(OH)2?
18. What mass of CS2 is produced when 25.8 g of C are reacted with 54.2 g of SO2 according to the equation
5C + 2SO2 CS2 + 4CO
What mass of the excess reactant will be left over?
19. What mass of P4 is produced when 23.8 g of Ca3(PO4)2, 14.2 g of SiO2, and 3.81 g of C are reacted according to the equation
2Ca3(PO4)2 + 6SiO2 + 10C P4 + 6CaSiO3 + 10CO
How many grams of each excess reactant will remain unreacted?
20. What volume of NO(g) at STP will be produced when 27.3 g of Cu reacts with 600.0 mL of 1.250 M HNO3(aq) according to the reaction
3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 2NO(g) + 4H2O(l)
CHEMICAL REACTIONS AND STOICHIOMETRY 4 CHEMISTRY 11 REVIEW VII.1
21. What mass of ICl can be produced from the reaction of 50.0 g of I2, 65.0 g of KIO3, and 250.0 mL of 1.50 M HCl according to the equation
2I2 + KIO3 + 6HCl 5ICl + KCl + 3H2O
22. Consider the reaction
K2Cr2O7 + 6NaI + 7H2SO4 Cr2(SO4)3 + 3I2 + 7H2O + 3Na2SO4 + K2SO4
(a) A 50.0 g NaI sample is 38.6% pure. What mass of I2 can the sample produce?
(b) Another sample of NaI, with a mass of 65.0 g reacts to produce 15.2 g of Cr2(SO4)3. What is the percentage purity of the NaI?
(c) A 35.0 g sample of pure K2Cr2O7 produces 9.67 g of H2O. What is the percentage yield?
(d) If the reaction has a percentage yield of 37.6%, what mass of NaI will be required to produce 50.0 g of I2?
CHEMICAL REACTIONS AND STOICHIOMETRY 5