SCH4U
Mr. McKay's Grade 12 Chemistry Review
SCH4U- Atomic Structure Review
1) Describe the contributions of the following scientists to our current understanding of atomic structure and the
quantum theory:
a) Bohr, b) DeBroglie, c) Heisenberg, d) Schrodinger, e) Pauli
2) Based on the quantum mechanical model of the atom:
a) What is an "orbital"'?
b) What is the maximum electron carrying capacity of the following energy levels: n=2, n=5
c) What orbital sub-levels would be found in the following energy levels: n=2, n=5
d) How would the number of electrons determined in 2(b) be distributed amongst the orbital sub-levels in 2(c)
(i.e.: number of e- per sub level)
3) a) Write the ground state electron configuration of a neutral atom of nitrogen.
b) Assign quantum numbers to each or the electrons in your nitrogen atom.
SCH4U- Bonding and Molecular Shapes Review
1) Use Lewis diagrams to draw the following molecules or ions. Once completed, use the VSEPR theory to predict
the shape of each. For each molecule, decide whether it is polar or non-polar.
a) PCl3 b) SiF4 c) CO32- d) H2S e) PO43- f) O3 g) CO h) NO312) Methane and fluoromethane are two very similar molecules. Despite their similarities, there is an 86°C difference
between their boiling points. Which of these two substances would have the higher boiling point? Explain your
answer.
3) The element iodine exists as solid crystals composed of I2 molecules. A chemist wishing to dissolve iodine has a
choice of two solvents; water and tetrachloromethane. Which of these two solvents would be the best choice?
Explain your answer.
4) Consider a molecule of ethanal.
a) What type of orbital hybridization is each atom in the molecule using for bonding?
b) What geometric arrangement would each of these orbitals take?
c) Describe the orbital overlap that accounts for each bond and specify the type of bond formed (sigma, pi)
d) What are the bond angles around each carbon atom in this molecule?
5) Consider the data in the following table for substances labeled 'A" to “G"
___________________________________________________________________________________________
Substance
Melting point (°C)
Boiling point (°C)
Solubility in H2O
Electrical Conductivity
as; solid/liquid/aq. sol.
A
-94
65
SOLUBLE
NO/NO/NO
B
1610
2230
INSOLUBLE
NO/NO/NA
C
119
445
INSOLUBLE
NO/NO/NA
D
660
2467
INSOLUBLE
YES/YES/NA
E
770
1500
Slightly SOLUBLE
NO/YES/slightly
F
-182
-164
INSOLUBLE
NO/NO/NA
G
2614
2850
SOLUBLE
NO/YES/YE5
____________________________________________________________________________________________
Classify each substance as to the type of solid it represents: molecular, metallic, ionic, network
Match the letter for each sample to one of the following substances (one letter per substance) and explain your
reasoning: quartz, CaO, Al, methanol, Sulfur, methane, KCl
6) a) Write a molecular structure for molecules for the following molecules.
b) Draw all possible resonance structures for each.
c) Indicate which structures include co-ordinate covalent bonds.
i) H2COii) N2H2
iii) BF3
iv) CO32- v) SO3
vi) SO32-
7) a) Calculate formal charges for each possible structure of the following three compounds.
b) Use these and the other rules from question 1 to decide which is the most likely to be the
naturally occurring structure.
c) What evidence would you look at to determine which structure actually is the natural one?
d) What would you conclude if the evidence did not match any of the possible structures?
8) Describe the shape and hybridization state of the central atom in the following molecules.
a) both SO42- structures in the previous question (are they the same?).
b) NH3
c) PCl5 d) XeF4 e) BCl3 f) H2O
9) What is the difference between an atomic orbital and a bonding orbital?
10) a) What evidence do we have that orbitals hybridize.
b) Sketch a 2s, 2p, and 2sp orbital.
11) Write out the atomic orbitals (in an energy-level diagram) that are present in Sulfur in:
a) its ground state,
b) after promoting electrons for bonding to make the left-hand SO42- molecule above
c) after hybridizing before bonding to make the left-hand SO42- molecule above
12) Describe the process by which sigma and pi bonds are formed, the type of atomic orbitals that
can do this, and sketch the shape of the bond.
13) Write out the types of bonding orbitals present in the molecules in question 2. Include both
the type of bonding orbital and the atomic orbitals that formed them.
14) a) Describe some of the properties that sigma bonds and pi bonds produce in a molecule.
b) What sort of bond can delocalize?
c) What does the existence of delocalized bonds help explain?
15) Why are the bond angles in water and ammonia not the same?
SCH4U- Organic Chemistry Review
1) Draw the structural formula for the
following compounds:
a) N,N-dimethyl-2-pentamine
b) 3-ethylcyclohexane
c) methylpropanal
d) 2-chloro-3-methyl-2-hexene
e) 2-ethoxypropane
f) propylbenzoate
g) N-ethylpropanamide
h) 2,3-difluorobutanoic acid
2) Name the compounds pictured here:
3) Complete the following chemical reactions by naming and drawing the molecular formula the organic product(s).
Assume all required conditions are available for each reaction, but state which conditions, if any, are necessary.
a) 3-methyl-1-butyne + 2Cl2
b) methane + excess O2
c) 2-methyl-3-pentanol + KMnO4
d) methylpropene + HBr
e) 2-methylbutanal + KMnO4
f) cyclopentene + H2O (w/ H2SO4 catalyst)
g) dimethyl-l,3.propandiol + KMn04
h) ethanoic acid + phenol
4) Consider the following organic compounds:
propanone, 2-propanol, 2-chloropropane, proponoic acid, and propane
a) For each compound, identify the type of intermolecular forces acting between molecules.
b) Rate the solubility of each compound in water as: insoluble, slightly soluble or very soluble
c) Arrange the compounds in order of increasing boiling point.
5) Name, identify the class of organic compound, and draw a structure diagram for all the isomers of C4H8O
6) List the steps (reactions) needed for the following synthesis problems.
a) What alkene could be converted to 2-pentanone?
b) What alkene could be converted to ethyl ethanamide?
c) What chloroalkane could be transformed into 1-butene?
SCH4U- Energy and Rates Review
1) When 13.4g of ammonium chloride dissolve into 2.00x102 g of water the temperature changes from 20.0°C to
15.3°C. Determine the molar enthalpy of solution of ammonium chloride and write a balanced thermochemical
equation for the reaction. Sketch an enthalpy diagram for this reaction. (Ans: +16.7kJ/mol)
2) The following chemical reaction occurs in a car battery:
Pb(s) + PbO2(s) + 2H2S04(aq) –> 2PbSO4(s) + 2H2O(l)
Given the following enthalpy of formation values, calculate the enthalpy change for the above reaction as written
(enthalpy of reaction) (Ans: -315.6 kJ)
PbO2(s)
H2S04(aq)
PbSO4(s)
H2O(l)
-277.0 kJ/mol
-909.3 kJ/mol
-902.1 kJ/mol
-285.5 kJ/mol
b) If it takes 39.5 kJ to start your car, what mass of lead (II) sulphate is produced when starting the car using the
battery reaction described in 'a'? (Ans: 75.8g)
3) The combustion of ethane is illustrated by the following equation:
C2H6(g) + 7O2(g) –> 4CO2(g) + 6H2O(g)
a) Show how the following equations can be combined using Hess’ Law to determine the enthalpy of combustion
of Ethane. (Ans: -3028 kJ)
1) C2H2(g) + 3O2(g) –> 2CO2(g) + 2H2O(g)
∆H = -1409 kJ
2) C2H4(g) + H2(g) –> C2H6(g)
∆H = -136.7 kJ
3) H2(g) + ½O2(g) –> H2O(g)
∆H = -214.6 kJ
b) If you wish to burn ethane as fuel to heat 550.0 g of water from 12.5 °C to 100.0 °C, how many moles of ethane
will be require? (Ans: 0.13 moles)
4) From your text on pages. 414-416 answer #13,14,15,16,18
5) For the reaction 3B(s) + 2C(aq) —> A(g) + 2F(aq), 15g of B is reacted. A calorimeter with 200.0 g of water is used to
evaluate the reaction. The water temperature changes from 25.0 oC to 12.5 oC over the course of the reaction. The
molar mass of B is 89.5 g/mol.
a) write a thermochemical equation with an energy term for the reaction as balanced.
b) write the balanced chemical equation with an associated ∆H term.
c) calculate the molar ∆H term for substance B in this reaction.
d) draw an energy diagram for this reaction as balanced.
6) Initial reaction rates for the reaction in question 1 are calculated starting from the given initial concentrations:
[B]i (M)
[C]i (M)
Rate of production of A (M/s)
0.1
0.1
0.011
0.2
0.1
0.039
0.1
0.3
0.013
a) Write a rate law equation for this reaction
b) Write a plausible rate limiting step for this reaction.
c) Is the reaction in question 1 a plausible rate limiting step? Why?
d) If a reaction A+2B —> C is a rate limiting step, what is its rate law expression?
e) Could the reactions A+B—>C+D and B+D—>C be a plausible mechanism for
the reaction in question 2d? Why?
7) The rate of production of F in the reaction for question 1 is to be 0.75 M/s.
What is the reaction rate for:
substance C?
substance B?
What is the overall reaction rate?
8) List the three criteria that a proposed reaction mechanism must satisfy.
9) The activation energy for a chemical reaction is 34.7 kJ/mol and the Arrhenius constant is
0.72 M/s.
a) Calculate the rate law constant, k, at a temperature of 27 oC.
b) Redraw your energy diagram from question 1d including the activation energy.
SCH4U- Introduction to Equilibrium
1) Write an equilibrium expression for the reaction in question 5 of the previous section.
2) a) If the K value for the reaction in question 1 is 1.7 at room temperature and the concentrations of the
components are [B]=0.15M, [C]=0.4M, [A]=2.1M, and [F]= 3.5M, is the system at equilibrium?
b) If the answer to is “no”, then in which direction will the system shift to approach equilibrium?
c) What would be the equilibrium expression for the reaction written in reverse?
d) Would it make any difference to the calculated equilibrium concentrations to use the reverse equation?
3) How would the reaction from question 5 in the previous section, if at equilibrium, react to the following changes:
a) The concentration of A is increased.
b) The amount of B is increased.
c) The concentration of F is increased.
d) The temperature of the system is increased.
e) The volume of the system is decreased.
f) A catalyst is added to the system.
g) An inert gas is added to the system.
h) A substance the precipitates C as a solid is added to the system.
4) In the reaction 2B(aq)—> C(aq) in which K=3.5 at room temperature, a reaction container is set up with a
concentration of 1.0 M of substance C, and no B. What will be the concentration of B and C at equilibrium?
5) a) What is the solubility of A2B if its Ksp is 0.001?
b) What is the Ksp of the salt CD3 if its solubility is 0.5 mol/L?
c) Will a 0.01 M solution of AC and a 0.02 M solution of DB (both soluble salts) precipitate A2B if
100.0 mL of each solution is mixed together?
6) Consider the following salts:
AgI, AgNO3, AgCl, Ag2CO3, Ag2CrO4
a) List these salts in order of increasing solubility.
b)Write the chemical equilibrium equation for the formation of an aqueous solution of the least soluble silver salt.
c) Determine the solubility in mol/L and in g/L for the least soluble silver salt in pure water.
(Ans: 9.2X10-9 mol/L and 2.2X10-6 g/L)
d)Determine the solubility in mol/L for the least soluble silver salt in pure water in a 0.025 M solution containing a
sodium salt with the same negative ion. (Ans: 3.5X10-15 mol/L)
7) You are given a 100.0 mL sample of 0.0010 M silver nitrate and 100.0 mL of solution made by dissolving
6.4X10-4 g of sodium carbonate (not sodium bicarbonate) in enough water to make 100.0 mL of solution. If the two
solutions are mixed at 25°C, will a precipitate of silver carbonate form? (Ans; Q = 8.0x10-12 )
8) From your text on page 457, #1-4; page 465 #1,2; page 481, #1-8
SCH4U -Acid/Base Equilibrium Review
1) Determine the pH of the following: (Ans: a: pH 12.4
a) 0.025M KOH solution.
b) 0.075M HN03 solution
b: pH 1.1)
2) Nicotinic acid is a weak monoprotic organic add with the formula C6H4NCOOH.
a) Write the equilibrium equation for nicotinic acid in water.
b) If a 0.050M solution of nicotinic acid has a pH of 3.1, determine the Ka of this acid. (Ans: 1.3x10-5)
3) Consider the following salts: KNO3, LiC6H5COO, N2H5Cl, LiCN, NH4Cl
a) Group the salts in to the categories: acidic, basic, neutral.
b) Write an equilibrium Ka or Kb expression for all the non-neutral salts in the list.
4) What volume of 0.0150M HNO3, is needed to titrate 30.0 mL of 0.0250M NaOH to the equivalence point?
5) Hydrosulphuric acid (H2S) is a weak acid with a Ka of 9.1x10-9
H2S + H2O --> H3O+ + HSa) Determine the pH af a 0.075M solution of this acid. (Ans: pH 4.6)
b) What is the percent dissociation of this acid? (Ans: 0.035%)
6) Hydrocyanic acid is a weak acid with a Ka of 4.9x10-10
HCN + H2O --> H3O+ + CNa) What is the Kb of the cyanide ion? (Ans: Kb= 2.0x10-5)
b) Determine the pH of a 0.15M NaCN solution. (Ans: pH 11.2)
7) a) What will be the pH of a 0.1 mol/L solution of the base B: if its Kb is 10-5?
b) What will be the pH of a 0.1 mol/L solution of the conjugate acid BH+?
c) What will be the pH of a solution made from 0.2 moles of B: and 0.3 moles of BH+ in one litre of
solution? This is the sort of situation one might have part way through a titration.
SCH4U -Redox Review
Answer the following in the text. Use the appendix tables from the text as needed (you will be provided with this
data on the exam).
Self-Quiz #1 to 7, 10 to 15
page 726: #2, 3, 4, 7, 8, 13, 15, 18