SCH 3U Exam Review Practice Questions
Unit 1: Matter and Chemical Bonding
1. What is the relationship between the number of proton, neutrons and electrons in an atom?
2. Two atoms respectively have a Z=12, A=26 and Z=14, A=26. Can these two atoms be classified as
isotopes of the same element? Give reasons for your answer.
3. Define: ionization energy, electron affinity, electronegativity, atomic radius, effective nuclear charge
(ENC), and shielding
4. Rank each of the following in order of increasing atomic size:
a) Mg, S , Cl
b) Al, B, In
c) Ne, Ar, Xe
d) Rb, Xe, Te
5. Rank each of the following in order of decreasing ionization energy:
a) Na, Li, Cs
b) S, Cl, Br
c) Cl, Ar, K
d) Ga, Ge, Se
6. Which element in the following pairs will have the lower electron affinity?
a) K or Ca
b)O or Li
c) S or Se
d) Cs or F
7. Calculate the difference in electronegativity for each bond and indicate the type of bond (covalent,
polar covalent, ionic)
a) Zn-O
b) Mg-I
c) Co-Cl
d) N-O
8. Draw the lewis structure to represent the following compounds:
a) SiO2
b) NaH
c) SeO3
d) NF3
e) XeF4
f)PCl5
9. Write the formula for the following compounds:
a) Silver chloride
b) Phosphorus pentachloride
c) Titanium (IV) oxide
d) Calcium oxide
e) Manganese (II) phosphide
f) carbon tetrahydride
g) Mercury (II) fluoride h) Iron (II) sulfide
10. Write the name of each compound:
a) HIO2
b) CsF
g) Al2(SO3)3
h) Fe(IO4)3
c) NaHSO4
d) K2Cr2O7
e) KClO4
f) N2Cl2
11. Write a balance chemical equation for the following:
a) Barium chloride reacts with Sodium carbonate
b) Iron reacts with copper (II) sulfate
c) ethyne (C2H2) reacts with oxygen gas
d) phosphorus pentachloride decomposes into its elements
e) Calcium reacts with chlorine gas
12. Complete and balance the following nuclear equations:
a) 21H + 31H  42He + _______
b) 23992U  _____ + 0-1 e
c) 23993Np  23994Pu + _____
d) 23892U  23490Th + 2 00γ + ______
13. Describe and explain the trends that exist in the periodic table for ionization energy, ionic radius,
electron affinity.
Unit 2: Quantities in Chemical Reactions
1. The isotopes of argon have the following relative abundances: Ar-36 0.34%, Ar-38 0.06% and Ar-40
99.66%. Estimate the average atomic mass of argon.
2. How many atoms of H are in a mixture of 3.49 X 1023 molecules of H2O and 78.1g of CH3OH?
3. In a reaction between sodium chloride and silver nitrate,
a) How many moles of NaCl react with 1 mol of silver nitrate?
b) What mass of silver nitrate reacts with 29.2g of sodium chloride?
4. Determine the percentage composition of the following:
a) CCl2F2
b) Pb3(PO3)4
5. Progesterone, a hormone in the human body, is made up of 80.2% C, 10.18% O and 9.62% H.
Determine the empirical formula for progesterone.
6. When a 0.5000g sample of citric acid was subjected to carbon-hydrogen combustion analysis, 0.6871g
of carbon dioxide and 0.1874g of water were produced. Using a mass spectrometer, the molar mass of
the citric acid was determined to be 192 g/mol.
a) What are the percentages of C, H and O in citric acid?
b) What is the empirical formula of citric acid?
c) What is the molecular formula of citric acid?
7. Powdered zince and sulfur react in an extremely rapid, exothermic reaction to produce zinc sulfide. A
6.00g sample of zinc is allowed to react with 3.35g of sulfur.
a) Determine the limiting reagent.
b) Calculate the mass of zinc sulfide expected
c) How many grams of the excess reactant will remain after the reaction is complete?
8. Ammonia can be produced in the lab by heating ammonium chloride with calcium hydroxide.
Products from this reaction include ammonia, calcium chloride and water. If 8.93g of ammonium
chloride is heated with 7.48g of calcium hydroxide, what mass of ammonia can be produced from this
reaction?
9. Consider a 7.35g sample of propane (C3H8):
a) How many moles of propane are in this sample?
b) How many molecules of propane are in this sample?
c) How many atoms of Carbon are in this sample?
Unit 3: Solutions and Solubility
1. What factors affect the rate of dissolving of a solid in a liquid?
2. Which of the following would you expect to be soluble in water?
a) KCl
b) CCl4
c) Na2SO4
d) C4H10
3. 10% W/W sodium hydroxide solution is used to break down wood fibre to make paper.
a) What mass of solute is needed to make 250mL of solution?
b) What is the molar concentration of the solution?
4. The concentration of sodium fluoride is maintained at 2.9 X 10-5 mol/L. What mass, in mg, of sodium
fluoride is dissolved in 1L of water? Express this concentration in ppm.
5. Calculate the mass of solute that is needed to prepare each solution below:
a) 250mL of 0.250mol/L calcium acetate
b) 1.8L of 0.35mol/L ammonium sulfate
6. Calculate the molar concentration of each solution formed after dilution.
a) 20mL of 6.0mol/L hydrochloric acid diluted to 70mL
b) 300mL of 12.0mol/L ammonia diluted to 2.50L
7. Hydrogen sulfide gas can be prepared by the reaction of sulfuric acid with sodium sulfide. Write the
net ionic equation for this reaction.
8. 50mL of 0.200mol/L Calcium nitrate is mixed with 200mL of 0.180mol/L potassium sulfate. What is
the concentration of the sulfate ions in the final solution?
9. A double displacement reaction occurs in an aqueous solution when magnesium phosphate reacts
with lead (II) nitrate. If 20.0 mL of 0.750 mol/L magnesium phosphate reacts, what is the maximum
mass of the precipitate that can be formed?
10. Phosphoric acid is reacted with sodium hydroxide. Given the laboratory data below, calculate the
unknown concentration of the acid:
Trial
1
2
3
4
Vol of acid
10.0 mL
10.0 mL
10.0mL
10.0mL
Conc. Of base
1.25M
1.25M
1.25M
1.25M
Final buret reading base
13.3 mL
25.0 mL
36.8 mL
48.4 mL
Initial buret reading base
0.4 mL
13.3 mL
25.0 mL
36.8 mL
Deep red
Pale pink
Pale pink
Pale pink
Vol. Base added
Colour at endpoint
Unit 4: Gases and Atmospheric Chemistry
1. A sample of oxygen gas occupies a volume of 10.0L at 546K. At what temperature in ·C would the gas
occupy at a volume of 5.0L?
2. A sample of nitrogen gas occupies 11.20L at 0·C and 101.3kPa. How many moles of nitrogen are there
in this sample?
3. Tetraphosphorus trisulfide reacts with oxygen gas to produce tetraphosphorus decoxide and sulfur
dioxide. If 5.3L of oxygen gas were consumed, how many litres of sulfur dioxide would be produced?
4. A 250.0mL balloon full of pure helium at 101.3 kPa is subjected to a pressure of 125.0kPa at a
constant temperature. What is the final volume of the balloon?
5. The head of a match contains approximately 0.75g of diphosphorus trisulfide. When the match is
struck on a rough surface, it explodes into flames producing diphosphorus pentaoxide and sulfur
dioxide. What volume of sulfur dioxide will be produced if the temperature is 26.5· C and the pressure is
102.8kPa?