SCH3U
REVIEW QUESTIONS FOR FINAL EXAM
MULTIPLE CHOICES
1. Glucose test paper changes colour in the presence of glucose. This observation signifies:
a) A chemical property of glucose test paper in response to glucose
2. Iron is a strong metal with a shiny surface. It is a solid at room temperature, but it can be heated
and formed into different shapes. These properties are called:
b) Physical
3. An element’s mass number:
c) Is the total number of protons and neutrons in the nucleus of an atom
4. The alkaline earth metals:
c) React with oxygen to form compounds called oxides. They also form salts upon
reaction with halogens.
5. As you go across a period:
b) The radius of an atom decreases. The effective nuclear charge increases as a proton
is added to each element as you go across the Periodic Table. Electrons are also
being added but they are all added to the same energy level, thereby not giving a
“cancel-out” effect of charge.
6. The electronegativity of Hydrogen is 2.20 and that of Chlorine is 3.16. **Hint: (∆EN)
c)
∆EN = 3.16 – 2.20 = 0.96. Now, read this ∆EN value from the Pauling scale.
HCl is a polar covalent compound.
7. The valence (-x) of the polyatomic ion, sulfate (SO4 -x) is:
b) –2
** 8. Was skipped on your copy
9. You observe
this material as:
WHMIS symbol on a chemical bottle. You immediately recognize
d) Oxidizing material
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10. When an iron nail is placed in a solution of copper(II)sulfate, the following reaction occurs:
Fe(s) + CuSO4(aq)  FeSO4 (aq) + Cu(s)
This type of reaction is called:
b) single displacement reaction
Terminology: All terms are used in your textbook. Refer to the Glossary and to the appropriate
chapters (see index).
Balance each of the equations from the formulas given, samples with answers shown
below:
1.
2.
3.
4.
5.
4Cu + O2 → 2Cu2O
CaCl2 + 2AgNO3 → 2AgCl + Ca(NO3)2
4H2 + O2 → 2H2O
6Mg + P4 → 2Mg3P2
H2SO4 + 2NaOH → 2H2O + Na2SO4
POLYATOMIC IONS:
Write the formulas for the following ions:
a)
b)
c)
d)
e)
Phosphate: PO4-3
Sulfate: SO4-2
Nitrate: NO3-1
Hydroxide: OH-1
Ammonium: NH4+
STRONG ACIDS:
HCl: hydrochloric acid
HNO3: nitric acid
H2SO4: sulfuric acid
STRONG BASES:
Sodium hydroxide, potassium hydroxide, calcium hydroxide
QUANTITATIVE CONVERSIONS:
Sample
Molar Mass
M (g/mol)
Mass of sample
(g)
Number of Moles
(n)
Number of Molecules
(N)
CH4
___16.05_______
52.58
____3.28_____
1.97 x 1024__
H2SO4
__98.09________
__5.30___
__0.0540_____
3.25 x 1022
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SHORT ANSWER:
1.
How did scientists calculate the average atomic mass of Carbon?
They used a weighted average of the masses of the stable isotopes of Carbon.
2.
You have identified 3 stable isotopes of Carbon, C-12, C13, C14, but you have only determined
the isotopic abundance of isotope C-14.
a) What additional data will you need in order to calculate the abundance of the other two
isotopes?
The masses (µ) of all three isotopes are required and the average atomic mass of
Carbon (on the Periodic Table) is also required.
b) Which isotope of Carbon is most abundant in nature? How do you know?
The average atomic mass of Carbon is 12.01 µ.
C-12 isotope is closest to the a.a.m. and is therefore the most abundant.
3.
You are given 50g of pure iron (III) sulfate.
a) Determine the total number of moles of iron (III) sulfate.
M Fe2(SO4)3 = 399.91 g/mol; n = m/M
n= __50g_____ = 0.12 mol
399.91 g/mol
b) Then, you are to prepare 500 mL of an aqueous solution of iron (III) sulfate using all of the
sample. What is the concentration (mol/L) of the solution?
C = n = 0.12 mol = 0.24 mol/L
V
0.500L
c) Write a step-by-step procedure to prepare the solution. Use proper names for glassware and
equipment.
Suggestions to answer this question:
Write in complete sentences.
1. Put on your splash goggles.
2.Use a scoopula to transfer the iron (III) sulfate to the 500 mL volumetric flask. A small
gravity funnel could be used to ensure all crystals are transferred without spillage.
3. Add a small volume of deionized water to the volumetric flask and gently swirl to
dissolve the solid particles.
4. Fill flask to the bottom of the meniscus. Adding the last few milliliters with an eye
dropper is advised.
5. Place cap on volumetric flask and gently mix the solution.
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4.
The Recommended Nutrient Intake (RNI) of iron, Fe, for women is listed as
14.8 mg per day.
Calculate the number of moles of elemental iron required by women, according to the RNI.
N = m/M = 0.0148 g / 55.85 g/mol
5.
= 2.65 x 10-3 mol
Your experiment has produced 60.0 grams of calcium carbonate, CaCO3 (s).
a) How many molecules of calcium carbonate were produced?
n = m/M = 60.0 g/ 100.09 g/mol = 0.599 mol
N = n NA = (0.599mol)(6.02x1023 molecules/mol) = 3.61 x 1023 molecules
b) How many atoms of CaCO3 (s) were produced?
3.61 x 1023 molecules x 5 atoms/molecule = 1.81 x 1024
6.
Label the Chemistry Equipment diagram. (see attached)
The equipment sheet handed out did not include a hot plate or a test tube rack. Review these.
7.
Write the balanced chemical reaction equation for the complete combustion of C4H10.
(Reminder: your two products are always water and carbon dioxide)
NOT ON EXAM: We’ll review again in Gr 12 Unit 1: Organic Chemistry
2C4H10 + 13O2 (g) → 8CO2 (g) + 10H2O (g)
8.
Explain “Like dissolves like”.
Polar solutes dissolve in polar solvents. Non-polar solutes dissolve in non-polar solvents.
-Ionic crystals with large ΔEN dissolve well in polar water molecules as do polar
molecular solutes such as HCl.
-Non-polar solutes such as I2 dissolve well in non-polar solvents such as kerosene.
9.
Solid crystals of BaCl2 are added to a beaker filled with 250 mL of water.
a) How do you know when the solution is saturated?
No more crystals will dissolve and crystals are observed in the bottom of the beaker.
b) What could you do to increase the rate of dissolving?
Stirring or agitating can increase the rate of dissolving. Heating the solution can also
provide kinetic energy to the molecules and increase the number of particle collisions.
c) If you must increase the solubility of BaCl2 in 200 mL of water, what must you do?
Heat the solution. Additional energy required to break the forces of attraction between
solute particles will increase the amount of solute that will be able to dissolve in the
volume of solution.
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d) Why does BaCl2 dissolve in water? Explain the criteria for dissolution with respect to
“Forces of Attraction”.
Forces of attraction between the solute, BaCl2, particles in their strongly held crystal
lattice must be overcome by strong forces (ion-dipole) between the solute and the solvent water
molecules. Some dipole-dipole forces of attraction between the water molecules must also be
overcome to make room for the solute ions as they are distributed evenly throughout the solution.
10.
11.
AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)
Convert each of the following:
a)
b)
c)
12.
Yes a reaction takes place.
A precipitate of silver chloride forms.
360 mL to L : 0.360 L
30 g H20: 30 mL
7.50 x 104 mg to kg : 0.075 kg
Electronegativity values can be used to predict the type of bond (ionic or covalent) that
forms between two atoms.
Use the electronegativity table and the electronegativity scale to determine the type of bond that
forms between Barium and Chlorine. Show your calculation.
Ionic Bond. ΔEN > 1.7
13.
a) Water is our Universal Solvent. Why do we give water this title?
Most solutes will dissolve, even if only to a small extent in water. Water will act as either
an acid or as a base in solution.
b) Is water a polar or non-polar solvent? polar
c) Write an equation to demonstrate water’s behavior as a base when an acid is added to water. Label
the conjugate acid and conjugate base.
HCl (aq) + H2O (l) → H3O+ (aq) + Cl- (aq)
acid
base
conjugate conjugate
acid
base
d) Draw a water molecule that accurately depicts its shape. Label its dipole/charges.
-Bent molecule ; Oxygen is δ- ; Hydrogen atoms are δ+
14. Two reactants are given to you. One is a chunk of solid zinc metal with a measured mass of 5.0 g.
The second reactant is a solution containing 0.200 mol HCl (aq).
Which reactant, zinc or hydrochloric acid (HCl), is the limiting reactant?
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
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mol Zn = m/M = 5.0g/65.39 g/mol = 0.076 mol
1 mol Zn
= 0.076 mol Zn
1 mol ZnCl2
x mol ZnCl2
x = 0.076 mol ZnCl2
2 mol HCl = 0.200 mol HCl
1mol ZnCl2
x mol ZnCl2
x = 0.100 mol ZnCl2
Once 0.076 mol of ZnCl2 has been produced, the reaction stops because the system has run out of
Zn (s). Zn limits the amount of products that can be obtained. Therefore,
the Limiting Reactant is Zn (s).
15.
When preparing for a lab experiment, a chemistry student must be aware of the following:
a) laboratory safety rules : list 5
b) chemical safety:
Hazards (Potential dangers that can cause harm) : HCl is corrosive.
Precautions (Things you can do to protect yourself and eliminate or
minimize the hazards): Wear splash goggles and gloves.
Emergency response (The action(s) you should take if an accident does
occur).
Call for your teacher so that she can neutralize
the acid with lime or use sand to clean it up!
Rinse hands under water if spilled and a
neutralizing first-aid solution is also available.
c) WHMIS symbols are on all chemical reagent bottles. Draw the possible symbols.
(All symbols are in your textbook.)