A) C) B) D) - English Montreal School Board · exactly the same as the water approaching the dam. B) ... Two of the most common substances used to ... industry and internal combustion

BIM, page 1 June 1997 Part A : This part of the exam comprises questions 1 to 13. Darken the letter of the answer

chosen in your answer booklet.

Question 1 Which graph below depicts the relationship between the volume of a gas and its temperature in Degrees Celsius?

D) B)

C) A)

BIM, page 2 Question 2 On August 26, 1986, 1 200 residents of a village in Cameroon, West Africa, died within a few minutes. The tragedy was attributed to a cloud of carbon dioxide that escaped from a lake inside a crater of an extinct volcano. Here is what happened :

For thousands of years, carbon dioxide, produced by underground reactions, accumulated in the cold, deep waters of the lake.

In 1986, an earthquake caused a landslide, permitting CO2 to escape from the surface of the lake. Because of atmospheric conditions near the volcano, the volume of CO2 increased. Because it is heavier than air, it drifted down the side of the mountain and asphyxiated the residents of the village in the valley below.

Knowing that the atmospheric conditions on August 26, 1997 favoured an increase in the volume of CO2, which combinations below might best describe atmospheric temperature and pressure that fatal day? A)

COLD temperature; HIGH pressure

B)

COLD temperature; LOW pressure

C)

HIGH temperature; HIGH pressure

D)

HIGH temperature; LOW pressure

BIM, page 3 Question 3

During a laboratory experiment, you put an unknown compound into some water. You observe a bubbling reaction. With the help of a syringe, you remove the gas produced.

Consider the following data :

RESULTS

Mass of the 140 mL syringe : 23.47 g

Mass of the syringe with 140 mL of the gas : 23.72 g

Temperature in the lab : 298.0 K

Pressure in the room : 101.0 kPa

Which of the following is most likely the identity of the gas produced and collected? A)

O2

B)

N2

C)

CO2

D)

H2

BIM, page 4 Question 4 During an experiment, a team of students observes the following changes in various samples of matter.

CHANGES 1. Alcohol burns. 2. Liquid water becomes gaseous. 3. The vapour condenses on the sides of the

flask. 4. Ice melts in the beaker.

A molecular model of one of the changes that matter undergoes is shown below.

Which change in matter does this molecular model illustrate? A)

Change number 1

B)

Change number 2

C)

Change number 3

D)

Change number 4

BIM, page 5 Question 5 You are given two unknown liquids. You mix 100 mL of liquid A at 80°C with 100 mL of liquid B at 20°C. The resulting mixture has a final temperature of 60°C. What can you conclude from these results? A)

The specific heat capacity of liquid A is less than the specific heat capacity of liquid B.

B)

The specific heat capacity of liquid A is equal to the specific heat capacity of liquid B.

C)

The specific heat capacity of liquid A is more than the specific heat capacity of liquid B.

D)

Liquid A and liquid B are identical in both nature and concentration.

Question 6 When an acidic solution comes in contact with a basic solution, the hydrogen ions combine with the hydroxide ions, producing water. Also, the metallic ions combine with the non-metallic ions, producing a salt, as in the diagram below :

Given that the neutralizing reaction described above releases heat, which of the following statements is correct? A)

The enthalpy of the reactants is greater than the enthalpy of the products.

B)

The enthalpy of the reactants is less than the enthalpy of the products.

C)

The change in enthalpy (∆H) is positive.

D)

The reaction is endothermic.


A lighter has a reservoir containing a flammable gas under pressure. When the lighter is ignited, two things occur : - gaseous butane escapes through an opening; - hot sparks are produced friction from the flint. The combustion of butane is exothermic.

Associate the expressions on the right with the numbers on the energy diagram on the left.

Energy Diagram

Reaction Proceeds

1

2

}}

3

4

5

E (kJ)

Expressions

a. The energy contained in butane when the

lighter is opened b. The energy associated with the butane

heated by the sparks c. The energy liberated by the combustion

of butane d. The energy contained in the products

formed by the combustion of butane (CO2(g) and H2O(g)).

A)

a-2, b-1, c-5 and d-4

B)

a-4, b-3, c-1 and d-5

C)

a-4, b-3, c-2 and d-5

D)

a-5, b-3, c-2 and d-4

BIM, page 7 Question 8 Oxygen and silicon are the most abundant elements present in the Earth’s crust. However, the two elements are very rarely found in the atomic state (Si, O). Generally they tend to exist in the form of compounds, such as SiO2. Which statement best explains the tendency of oxygen atoms and silicon atoms to combine, forming SiO2? A)

The total amount of energy contained in one atom of silicon and two atoms of oxygen is greater than the energy contained in one molecule of SiO2.

B)

The total amount of energy contained in one atom of silicon and two atoms of oxygen is less than the energy contained in one molecule of SiO2.

C)

The total amount of energy contained in one atom of silicon and two atoms of oxygen is equal to the energy contained in one molecule of SiO2.

D)

Atoms of oxygen and silicon are radioactive.

BIM, page 8 Question 9 An ecologist, experimenting with atmospheric equilibrium, wishes to promote the reproduction of highly photosynthetic algae. He uses the following equation for photosynthesis :

6 H2O + 6 CO2 + energy from sunlight → C6H12O6 + 6 O2

After having selected 5 appropriate species of algae, he decides to measure their rate of photosynthesis. Which of the following procedures can be used to make the appropriate calculations for equal quantities of each species of algae?

1. Measure the mass of CO2 used up per unit of time.

2. Measure the variation in pH value in the water per unit of time.

3. Measure the solubility of CO2 and the solubility of oxygen in water.

4. Measure the volume of oxygen produced per unit of time.

5. Measure the quantity of energy contained in one mole of C6H12O6. A)

1 and 2

B)

1 and 4

C)

2 and 4

D)

3 and 5

BIM, page 9 Question 10 Curves 1 and 2 on the graph below represent energy pathways for the same chemical reaction. The reaction rate is faster for pathway number 2.

Chemical Reaction

Reactants

Products

REACTION PROCEEDS

1--

2--

ENERGY

Which factor is most probably responsible for the pathway in curve 2? A)

Increase in temperature

B)

Increase in contacting surface area

C)

Decrease is concentration of reactants

D)

Presence of a catalyst

BIM, page 10 Question 11 In order to study the conditions in a system at equilibrium, some iodine crystals were placed in alcohol, as in the diagram below.

Alcohol

Iodinecrystals

The iodine-alcohol solution quickly became reddish-colored. The color of the solution and the quantity of non-dissolved iodine crystals did not change over a period of a few days.

Which analogy might best explain the dynamics, at the microscopic level, of this equilibrium system? A)

A dam where the water level is constant. The amount of water leaving the dam is exactly the same as the water approaching the dam.

B)

A hockey game in which six players are on the ice at the same time. As one player leaves the bench to join the play, another player goes to the bench.

C)

A line-up at the cash in the cafeteria. As soon as a student pays, the length of the line-up decreases.

D)

A full dance club on a Saturday night. As soon as one customer leaves the club, the doorman lets in a new customer.

BIM, page 11 Question 12 Various metal strips V, W, X, Y and Z are inserted into beakers containing solutions of the various ions of those metals. Reactions are observed in beakers 1, 3 and 4.

Reaction No reaction Reaction Reaction No reaction

Based on an analysis of the preceding results, which of the following combinations will give the greatest electrical potential difference? A)

V - W2+

(aq)

B) V - X2+

(aq)

C) V - Y2+

(aq) D)

V - Z2+

(aq)

BIM, page 12 Question 13 During an experiment dealing with the factors that influence the rate of rust formation (slow oxidation), a team of students obtain the following results :

RESULTS

N°

DESCRIPTION

RESULT

Control Nail exposed to air and humidity

Moderate rusting

1

Nail exposed to dry air only

No rust

2

Nail exposed to air, humidity and salt

Rapid rusting and extensive rusting

3

Nail partially wrapped in aluminum foil, exposed to air and humidity

Less rust than in control test tube

4

Nail covered in grease, exposed to air and humidity

No rust

Which experimental result above best justifies the technological applications below?

a. A manufacturer of electronic equipment inserts a porous bag into his packaging. This bag contains a dessicator. (A drying agent.)

b. A chemist suggests the addition of anti-oxidant wrapping to certain food products before

they are put on shelves for sale.

c. Every spring, your father paints the swing. A)

a-1, b-3 and c-4

B)

a-2, b-1 and c-3

C)

a-2, b-3 and c-4

D)

a-4, b-2 and c-1

BIM, page 13 Part B : This part of the exam comprises questions 14 to 25. Do all the work required in your

answer booklet.

Question 14 Which two of the following liberate more energy than they absorb?

1. Ice melts on a sidewalk.

2. Clothes dry on a line.

3. Dissolving 20 g of CaCl2 in 100 mL of water at 80°C causes the solution to boil.

4. Fog forms on the mirror in the bathroom.

5. Water is decomposed by an electric current.

6. Carbon dioxide escapes when a soft drink can is opened. Question 15

Heat

Fuel Oxygen

Any measure used to extinguish a fire usually tries to reduce or eliminate one or more of the three components of the fire triangle. Two of the most common substances used to extinguish fires are water and carbon dioxide.

A) Which component of the fire triangle does water reduce or eliminate? B) Which component of the fire triangle does carbon dioxide reduce or eliminate?

BIM, page 14 Question 16 The winner of a science contest will be the group of students that produces the largest quantity of hydrogen gas in the shortest amount of time. Each group of students receives 1g of magnesium and 500 mL of hydrochloric acid having a concentration of 0.5 mol/L. and is given the following equation :

Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) Conditions : - The quantities of magnesium and acid cannot be increased. - A catalyst is not available. In a brainstorming session, your group identifies two experimental conditions which are likely to increase the rate of reaction. What are these two conditions? Question 17

SO2

SO2

SO2

When the sulfur dioxide emitted by the metallurgical industry and internal combustion engines in automobiles combines with oxygen in the air, the reaction is the following : 2 SO2(g) + O2(g) → 2 SO3(g) + 193 kJ Seeing how this reaction is a reversible one, and the planet Earth a possible equilibrium system, your classmate states that the formation of sulfur trioxide would be favored by these conditions : a cold winter day with high atmospheric pressure.

Considering Le Chatelier’s principle, do you believe these two conditions will shift equilibrium favoring sulfur trioxide production? Justify your answer.

BIM, page 15 Question 18 Problem During an experiment, you are asked to qualitatively compare the strength of two different acids of known concentrations.

Concentrations of acid X = 2 × 10-2 mol/L Concentrations of acid Y = 2 × 10-3 mol/L

Experiment You decide to measure the pH of the two acids and you obtain the following results : 100 mL of acid X (2 × 10-2 mol/L) with 10 drops of universal indicator has the same color as 100 mL of acid Y (2 × 10-3 mol/L) with 10 drops of the same indicator. Using the results obtained, compare the strengths of the two acids. Question 19 The diagram below illustrates a standard Cu/Cu2+//Ag/Ag+ cell. The electrolytic solutions have a concentration of 1 mol/L and are kept at 25°C.

Calculate the potential difference of this cell. Show your work

BIM, page 16 Question 20 Three identical cylinders contain different gases at the same temperature and pressure.

Cylinder n°1 contains 16.0 g of oxygen gas.

Cylinder n°2 contains helium.

Cylinder n°3 contains 20.0 g of gas.

A) What mass of helium is contained in cylinder n°2? B) What could be the identify of the gaseous element in cylinder n°3? Question 21 Acetylene (C2H2) is a colorless, flammable gas used in welding, according to the equation below :

2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) If welding a piece of metal consumes 13 g of acetylene, calculate the volume of carbon dioxide (CO2) produced. Conditions in the workshop are 20°C and 105 kPa. Show your work.


StyrofoamThermometer

Water

During a calorimetry experiment, 2.01 g of LiCl(s) are dissolved in 100 mL of water. The temperature of the water increased from 22.0°C to 25.0°C.

What quantity of heat energy is produced when 1 mol of LiCl is dissolved? Show your work. Question 23 Consider the following reactions :

1) 3 C(s) + 4 H2(g) → C3H8(g) + 104 kJ

2) C(s) + O2(g) → CO2(g) + 394 kJ

3) H2(g) + 1/2 O2(g) → H2O(g) + 242 kJ Calculate the change in enthalpy for the combustion of one mole of propane, as in this equation :

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) Show your work.

BIM, page 18 Question 24 Methyl alcohol (CH3OH(1)) is generally used as a fuel to heat the oil in fondue sets. What mass of methyl alcohol is needed to heat 1.10 kg of fondue oil from 22.0°C to 98.0°C? N.B. : Specific heat capacity of fondue oil is : 8.9 kJ/kg•K

Equation for the combustion of methyl alcohol is :

CH3OH(1) + 3/2 O2(g) → CO2(g) + 2 H2O(g) + 639 kJ Show your work. Question 25 Compounds A and B react to form compounds C and D, according to the equation below :

A(aq) + B(aq) ↔ C(aq) + D(aq) A) An initial solution of the above is prepared. One litre of it is analyzed at equilibrium and the

following results were obtained : The solution contained 0.010 mol of A, 0.020 mol of B, 0.010 mol of C and 0.040 mol of D.

What is the equilibrium constant?

Show your work.

B) A new solution is prepared (1.0 L) at the same temperature and pressure.

If the equilibrium concentrations of A, B and C are all equal to 0.010 mol/L, what is the equilibrium concentration of D?

Show your work.

BIM, page 19

Laboratory exam

THE RELATION BETWEEN DENSITY AND SPECIFIC HEAT CAPACITY Problem One of your friends claims that the greater the density of a material, the higher is its specific heat capacity. Do you agree with your friend? Verify your prediction experimentally. Material

- 3 metal blocks - 3 polystyrene cup - thermometer - 1 insulating lid - hot water - graduated cylinder - cold water - balance (±0.01 g)

The three metal blocks are :

1) Magnesium (1.74 g/cm3) or aluminum (2.70 g/cm3) 2) Zinc (7.14 g/cm3) or tin (7.30 g/cm3) 3) Nickel (8.90 g/cm3) or copper (8.96 g/cm3) or lead (11.4 g/cm3)

Present the results of your research in the form of a laboratory report.

Name : ____________________________

Group : _____ Date : ____________

CHEMISTRY 534

Answer Booklet

Secondary V

BIM, page 21 CORRECTION KEY PART A Questions 1 to 13 2 marks or 0 marks per correct answer. 1- [ A] [ ] [ ] [ ] 2- [ ] [ ] [ ] [ D ] 3- [ ] [ ] [ C ] [ ] 4- [ ] [ B ] [ ] [ ] 5- [ ] [ ] [ C ] [ ] 6- [ A ] [ ] [ ] [ ] 7- [ ] [ ] [ C ] [ ]

8- [ A ] [ ] [ ] [ ] 9- [ ] [ B ] [ ] [ ] 10- [ ] [ ] [ ] [ D ] 11- [ ] [ B ] [ ] [ ] 12- [ ] [ ] [ ] [ D ] 13- [ A ] [ ] [ ] [ ]

PART B Questions 14 to 25 Question 14 Number 3 and number 4 2 marks per correct answer. Total : 4 marks Question 15 A) Water reduces or eliminates the «heat» component of the fire triangle. B) CO2 reduces or eliminates the «oxygen» component of the fire triangle. 2 marks per correct answer. Total : 4 marks

BIM, page 22 Question 16 1. Increase the reactants’ contact surface area by changing the magnesium into little pieces. 2. Increase the temperature of the reactants.

Also : Increase (H+ ) by boiling away some of the acid solution. 2 marks per correct answer. Total : 4 marks Question 17 Prediction : Yes, equilibrium should favor the production of SO3. Justifications : Since this is an exothermic reaction, a decrease in temperature should favor the

products.

Since the number of reacting molecules is higher than the number of product molecules, an increase in pressure should favor the products.

5 marks (1 mark for the prediction, 2 marks for each justification) Question 18 Acid Y is stronger than acid X. or The dissociation of acid Y is greater than that for acid X. 4 marks or 0 marks Question 19 Cu → 2e- + Cu2+ E° = -0.34 V 2 Ag+ + 2e- → 2 Ag E° = 0.80 V Cu + 2 Ag+ → 2 Ag + Cu2+ E° = 0.46 V 4 marks or 0 marks

BIM, page 23 Question 20 A) Cylinder no 2 should contain 2.0 g of Helium. B) Cylinder no 3 could contain Argon. 2 marks per correct answer. Total : 4 marks Question 21

Amount of C2H2 used : 13 g/26 g•mol-1 = 0.5 mol

Amount of CO2 produced from the balanced equation : 1 mol

P = 105 kPa T = 293 K

Volume of CO2 produced

PV = nRT or V = P

nRT

V = (1 mol) (8.31 kPa•L) (293 K) = 23.2 L

(mol K) (105 kPa) 4 marks Appropriate procedure and correct final answer. 3 marks Appropriate procedure, but incorrect final answer because of minor errors such as errors in

calculation or transcription or an incorrect or missing unit of measure or a number incorrectly rounded off.

2 marks Appropriate procedure, but incorrect final answer because of major errors such as an incorrect application of a law, a formula or a rule.

1 mark Partially appropriate and correctly completed procedure. 0 marks Procedure inappropriate or missing, regardless of the final answer.

BIM, page 24 Question 22 - Quantity of heat energy produced by 2.01 g of LiCl(s)

Q = mc∆T = (0.100 kg) (4.19 kJ) (3.0 K) = 1.3 kJ (kg) (K)

- Quantity of energy produced by 42.4 g (1 mol) of LiCl

g 2.01

g) (42.4 kJ) (1.3 = 27.4 kJ/mol

4 marks Appropriate procedure and correct final answer. 3 marks Appropriate procedure, but incorrect final answer because of minor errors such as errors in



1 mark Partially appropriate and correctly completed procedure. 0 marks Procedure inappropriate or missing, regardless of the final answer. Question 23 1) C3H8(g) + 104 kJ → 3 C(s) + 4H 2(g) 2) 3 C(s) + 3 O2(g) → 3 CO2(g) + 1 182 kJ 3) 4 H2(g) + 2 O2(g) → 4 H2O(g) + 968 kJ C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H20(g) + 2 046 kJ 4 marks Appropriate procedure and correct final answer. 3 marks Appropriate procedure, but incorrect final answer because of minor errors such as errors in



1 mark Partially appropriate and correctly completed procedure. 0 marks Procedure inappropriate or missing, regardless of the final answer.


Q = mc∆T = Kkg

K)(76 kJ) (8.9 kg) (1.10

•= 744 kJ

1 mole CH3OH(1) = 32 g

Mass of methanol used =kJ) (639

kJ) (744 g)(32 = 37.3 g

4 marks Appropriate procedure and correct final answer. 3 marks Appropriate procedure, but incorrect final answer because of minor errors such as errors in



1 mark Partially appropriate and correctly completed procedure. 0 marks Procedure inappropriate or missing, regardless of the final answer. Question 25 A) At equilibrium, K = [C] [D] / [A] [B]

mol/L) (0.020 mol/L) (0.010

mol/L) (0.040 mol/L) (0.010 = 2.0

B) In the new solution, [C] [D] / [A] [B] = 2.0

)mol/L (0.010

[D] mol/L) (0.0102 = 2.0

[D] = 0.020 mol/L

2 marks per correct answer. Total : 4 marks

BIM, page 26 Question 26 LABORATORY REPORT Title : Density and Specific Heat Capacity. Objective : To determine experimentally whether there is a relationship between density and specific

heat capacity. Hypothesis (Example) As density increases, specific heat capacity decreases. 5 marks for any coherent hypothesis. Procedure (Example) 1. Calculate the heat capacity of the three given metals.

- Determine the mass of the given sample. - Measure the temperature of 100 mL of hot water. - Place the sample (at room temperature) in the hot water. - Measure the new temperature of the water. - Measure the specific heat capacity of the sample using the formula :

Csample = )( sample

water

Tm)T(mc

∆∆

2. Compare the variation in densities with the variations in specific heat capacity. 5 marks Result (Example) Metal

m (g)

Ti

metal (°C)

Ti

water (°C)

Tf

(°C)

∆∆T

metal (°C)

∆∆T

water (°C)

Aluminum

73.5

21.5

48.0

44.0

22.5

4.0

Zinc

27.9

21.5

45.0

44.0

22.5

1.0

Lead

40.2

21.5

50.0

49.0

27.5

1.0

5 marks

BIM, page 27 Calculations (Example) Calculation of specific heat capacity

aluminum =)( aluminum

water

Tm

)T(mc

∆∆

= C)(22.5 g) (73.5 C)(g

C)(4 J) (4.19 g) (100.0

°°°

= 1.0 J/g°C or 1.0 kJ/kg°C

czinc =)( zinc

water

Tm

)T(mc

∆∆

= C)(22.5 g) (27.9 C)(g

C)(1 J) (4.19 g) (100.0

°°°

= 0.7 J/g°C or 0.7 kJ/kg°C

clead =)( lead

water

Tm

)T(mc

∆∆

= C)(27.5 g) (40.2 C)(g

C)(1 J) (4.19 g) (100.0

°°°

= 0.4 J/g°C or 0.4 kJ/kg°C

5 marks Example of an appropriate conclusion : Comparison of the two properties :

Density (g/cm3)

Specific heat capacity

(kJ/kg°C) Aluminum

2.7

1.0

Zinc

7.0

0.7

Lead

10.1

0.4

As density increases, it appears that specific heat capacity decreases. 5 marks

BIM, page 28 /25 marks

Documents

A) C) B) D) - English Montreal School Board · exactly the same as the water approaching the dam. B) ... Two of the most common substances used to ... industry and internal combustion