Kinetics MCQ
April 18, 2017 | Author: Ng Swee Loong Steven | Category: N/A
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HKDSE Chemistry A Modern View Part IX Rate of Reaction
Section 38.1 1 Which of the following reactions is the fastest? A. B. C. D.
6CO 2 (g) + 6H 2 O(l) C 6 H 12 O 6 (aq) + 6O 2 (g) 4Fe(s) + 3O 2 (g) + 2H 2 O(l) 2Fe 2 O 3 • H 2 O(s) C 6 H 12 O 6 (aq) 2C 2 H 5 OH(aq) + 2CO 2 (g) 2C 2 H 6 (g) + 7O 2 (g) 4CO 2 (g) + 6H 2 O(l)
2 Which of the following reactions has the slowest rate? A Reaction between hydrochloric acid and copper(II) carbonate B. Reaction between dilute sulphuric acid and barium nitrate solution C. Reaction between methane and chlorine in sunlight D. Decay of fruit 3 Which of the following reactions is the slowest? A. Neutralization of HCl(aq) and NaOH(aq) B. Reaction of potassium and water C. Corrosion of iron D. Displacement reaction of Mg in CuSO 4 (aq) Section 38.2 4 When 50 cm3 of 0.20 M hydrochloric acid was mixed with excess sodium thiosulphate solution, the following reaction occurred. S 2 O 3 2(aq) + 2H+(aq) SO 2 (aq) + H 2 O(l) + S(s) 0.161 g of S was produced in 2 minutes. What is the average rate of production of S? A. B. C. D.
8.05 × 102 g s1 1.34 × 103 g s1 0.417 cm3 s1 1.67 × 103 M s1
5 The following graph shows the volume of hydrogen gas produced against time.
1
Volume of hydrogen gas (cm3)
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Time of reaction (min) Which of the following statements about the above graph is INCORRECT? A.
The average rate of the reaction is about 7.25 cm3 min1.
B. C. D.
The average rate between t = 1 min and t = 3 min is about 13.5 cm3 min1. The instantaneous rate at t = 1 min is about 23.0 cm3 min1. The instantaneous rate at t = 2 min is about 21.0 cm3 min1.
6 Which of the following can be shown by a rate curve? (1) Instantaneous rate of a reaction (2) Average rate of a reaction (3) Amount of reactants/products at a particular time A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 7 Which of the following statements concerning a rate curve is/are true? (1) The initial rate must be the fastest. (2) If the slope of the tangent equals zero, then the reaction stops. (3) The slope of the tangent must decrease from the largest value to zero. A. (1) only B. (2) only 2
HKDSE Chemistry A Modern View Part IX Rate of Reaction
C. D.
(1) and (3) only (2) and (3) only
8 5 g of calcium carbonate takes 250 s to react with the solution of hydrochloric acid completely. What is the average reaction rate of the reaction? A. B. C. D.
0.16 mol s1 0.020 mol s1 2.0 × 104 mol s1 2.0 × 105 mol s1
9 When 10 cm3 of 1.0 M acidified potassium permanganate is mixed with excess ethanedioate, the purple colour of the solution disappears after 40 s. Calculate the average reaction rate of the reaction. A.
0 M s1
B. C. D.
0.025 M s1 0.050 M s1 40 M s1
10 The rate curve of the amount of carbon dioxide produced when an acid reacts with a carbonate is plotted. When is the rate of the reaction the fastest? A. The graph is the steepest. B. C. D.
The graph is at 45 to the horizontal. The graph is half finished. The graph is horizontal.
11 Instantaneous rate can be obtained from a concentration-time graph. Which of the following methods is correct? A. Multiplying the concentration by time B. Measuring the slope of the graph at that instant C. Measuring the area under the graph D. Dividing the concentration by time 12 A chemical reaction completed in 10 minutes and released 0.16 g of oxygen gas. What 3
HKDSE Chemistry A Modern View Part IX Rate of Reaction
is the average rate of this reaction? A. B. C. D.
8.33 × 106 mol s1 9.33 × 105 mol s1 5.00 × 104 mol s1 8.00 × 103 mol s1
13 Which of the following methods are possible to quench a reaction? (1) Cooling the reaction mixture with an ice bath (2) Removing one or more of the reactant(s) (3) Diluting the reaction mixture (4) Adding a catalyst A. (1), (2) and (3) B. (1), (2) and (4) C. (1), (3) and (4) D. (2), (3) and (4) 14 The rate of formation of O 3 (g) is 2.0 × 107 mol dm3 s1 for the reaction: 3O 2 (g) 2O 3 (g) What is the rate of disappearance of O 2 (g) in mol dm3 s1? A. 1.3 × 107 B. 2.0 × 107 C. 3.0 × 107 D. 4.5 × 107 15 A reaction follows the concentration-time diagram. Which of the following values is closest to the instantaneous rate for this reaction at the 20th second?
4
Concentration (M)
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Time (s) A.
5 × 103 M s1
B. C. D.
5 × 103 M s1 2 × 103 M s1 2 × 103 M s1
16 Which of the following can be used to determine the rate of reaction at a specific time from a graph of concentration against time? A. Concentration at that time divided by the time B. Logarithm of the concentration divided by the time C. Slope of the graph at that time D. Logarithm of the slope divided by the time 17
Concentration (M)
What is the initial rate of the reaction (in mol dm3 s1) represented by this graph?
Time (s) A.
0.08
B.
0.08 5
HKDSE Chemistry A Modern View Part IX Rate of Reaction
C.
0.02
D.
0.02
18 Based on the definition for rate of reaction, which of the following is a unit of reaction rate? A. B. C. D.
mol dm3 mol s2 dm3 min3 mol dm3 min1
19 Which of the following statements is correct for the reaction below? 4P + Q 2R + 2S A. The rate of formation of R is one half the rate of disappearance of Q. B. The rate of decrease of Q is one quarter of the rate of disappearance of P. C. The rates of formation of R and S are not equal. D. The rate of formation of S is double the rate of disappearance of P. 20 Consider the esterification between ethanol and ethanoic acid in the presence of an acid catalyst. The concentration of ethyl ethanoate builds up to 0.68 mol dm3 in 2 minutes. Calculate the average rate of the reaction. A. B. C. D.
0.68 mol dm3 min1 0.34 mol dm3 min1 0.68 mol min1 0.34 mol min1
21 Combustion of methane gives carbon dioxide as one of the products. CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O(l) The concentration of carbon dioxide increases from 0 to 2 × 102 mol dm3 in 0.01 seconds. What is the average rate of decrease of O 2 (g) concentration? A. B. C. D.
0.02 mol dm3 s1 0.04 mol dm3 s1 2 mol dm3 s1 4 mol dm3 s1
6
HKDSE Chemistry A Modern View Part IX Rate of Reaction
22 Copper(II) ion reacts with ammonia molecules to form a deep blue complex: Cu2+(aq) + 4NH 3 (aq) [Cu(NH 3 ) 4 ]2+(aq) The average rate of decrease of ammonia is 1.6 × 102 mol dm3 s1. Calculate the average rate of increase of the complex concentration. A. B. C. D.
6.4 × 102 mol dm3 s1 3.2 × 102 mol dm3 s1 4.0 × 103 mol dm3 s1 2.0 × 103 mol dm3 s1
23 The average reaction rate of the complete reaction A B + C was 0.15 mol dm3 s1. If the time taken for the reaction to complete was 30 seconds, what was the total change in concentration of A? A.
0.0050 mol dm3
B. C. D.
0.75 mol dm3 4.5 mol dm3 20 mol dm3
24 Which of the following statements concerning the tangents to the rate curve is INCORRECT? A. The slope of the tangent represents the rate of the reaction. B. The tangent at time zero is usually the steepest. C. The slope of the tangent is equal to 0 when t = 0. D. The steepness of the tangents will decrease as the reaction proceeds. 25 5 g of magnesium ribbon of 70% purity was added to 200 cm3 of 0.050 M hydrochloric acid. The reaction took 50 seconds to complete and volume of gas collected was 4800 cm3. Which of the following statements is correct? A. Magnesium ribbon is the limiting reagent. B. Hydrochloric acid is the limiting reagent. C. D.
The rate of reaction of first 30 seconds is 100 cm3 s1. The average rate of mass decrease of magnesium is 0.07 g s1.
26 Which of the following is NOT a unit of chemical reaction rate? 7
HKDSE Chemistry A Modern View Part IX Rate of Reaction
A. B. C. D.
s mol1 cm3 s1 g min1 mol dm3 s1
27 When 10.6 g of anhydrous sodium carbonate was added to 200.0 cm3 of 1.0 M sulphuric acid at room conditions, the reaction stopped in 40 seconds. At the same time, 2400 cm3 of carbon dioxide was produced. Which of the following statements about the reaction is INCORRECT? A. B.
The average rate of decrease in mass of sodium carbonate was 15.9 g min1 The average rate of decrease in concentration of the acid was 0.0125 mol
C. D.
dm3 s1 The average rate of increase in volume of carbon dioxide was 60 cm3 s1 Sodium carbonate and sulphuric acid just reacted completely.
28 A rate curve is obtained when anhydrous sodium carbonate reacts with dilute hydrochloric acid. At which point on the rate curve below is the reaction rate highest? Pressure of gas
A B C
D
Time
29 Which of the following diagrams shows a correct rate curve for a chemical reaction?
8
HKDSE Chemistry A Modern View Part IX Rate of Reaction
A.
Amount of product in the reaction
B.
Time
Time C.
Amount of product in the reaction
Time
Amount of product in the reaction
D.
Amount of product in the reaction
Time
30 When excess dilute nitric acid reacts with magnesium carbonate, the reaction gradually becomes slower and finally stops. Which of the following statements correctly explains this situation? A. An insoluble layer of magnesium nitrate is formed. B. The magnesium carbonate is gradually used up. C. The nitric acid is all used up. D. The layer of carbon dioxide bubbles covers the magnesium carbonate. 31 The experiment shown in the diagram was set up and the syringe reading was noted at intervals.
9
HKDSE Chemistry A Modern View Part IX Rate of Reaction
rubber connecting tubing
gas syringe
dilute HCl MgCO 3 (s) A graph of the syringe readings against time was plotted. Which of the following curves would be obtained? Volume of gas A B C
D Time
32 When steam is passed through a red-hot magnesium ribbon inside a combustion tube, a reaction occurs and the temperature of the magnesium ribbon increases. What does this indicate? A. The reaction is reversible. B. Steam contains impurities. C. The reaction is exothermic. D. Magnesium is an oxidizing agent. 33 The graph shows how the total volume of carbon dioxide produced by the reaction between dilute nitric acid and excess calcium carbonate varied with time.
10
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Total volume of carbon dioxide produced P
Q
Time Which of the following statements about section PQ of the curve is correct? A. The speed of reaction is at maximum. B. All calcium carbonate has reacted. C. No more carbon dioxide is being produced. D. The concentration of the acid is increasing. 34 Which of the following methods of obtaining the instantaneous rate from a concentration-time graph is correct? A.
By equating the reaction rate with the concentration of reactant at that
B. C. D.
instant. By measuring the slope of the tangent to the curve at that instant. By measuring the area under the graph from time zero to that instant. The instantaneous rate cannot be obtained from a concentration-time graph.
35 A chemical reaction releases 0.16 g of oxygen gas in 10 minutes and reaches completion. What is the average rate of this reaction? A. B. C. D.
8.33 × 106 mol s1 1.67 × 105 mol s1 5.00 × 104 mol s1 1.00 × 103 mol s1
Section 38.3 36 Which of the following methods can be used to quench a reaction? (1) Cooling the reaction mixture rapidly in ice (2) Removing the catalyst by adding another reagent (3) Diluting the reaction mixture with a large amount of ice water A. (1) and (2) only 11
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B. C. D.
(1) and (3) only (2) and (3) only (1), (2) and (3)
37 Which of the following statements about the reaction between ethyl ethanoate and dilute sodium hydroxide solution is INCORRECT? A. The concentration of a reactant at regular time intervals can be determined by titrimetric analysis. B. Ethanol is formed in the reaction. C. The reaction can be quenched with ice water. D. This reaction is regarded as esterification. 38 2MnO 4 (aq) + 5H 2 O 2 (aq) + 6H+(aq) 2Mn2+(aq) + 8H 2 O(l) + 5O 2 (g) Which of the following methods is/are possible for monitoring the progress of the above reaction? (1) Titrimetric analysis (2) Measuring the change in colour intensity by colorimetry (3) Measuring the change in volume of gas A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 39 Which of the following methods can be used to quench a reaction? (1) Cooling the reaction mixture slowly (2) Removing one of the reactants (3) Diluting the reaction mixture with cold water A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 40 What is/are the advantage(s) of using titrimetric analysis to follow the progress of a reaction? 12
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(1) Only simple apparatus like pipette is required. (2) The reaction does not need to be quenched. (3) There is a continuous monitoring of the progress of reaction. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 41 Which of the following reactions CANNOT be followed by using the method of measuring the change in pressure of a gas? A. Na 2 CO 3 + HCl B. Zn + CH 3 COOH C. Na 2 SO 3 + CH 3 COOH D. Zn + HCl 42 Concerning the method used to study the progress of a chemical reaction between sodium thiosulphate and hydrochloric acid by measuring the change in transmittance of light through the reaction mixture, which of the following statements is correct? A. The transmittance of light through the solution is affected by the formation of sulphur dioxide. B. A data-logger is required in this method. C. The rate of the reaction is directly proportional to the time taken for the ‘blot out’ of the cross. D. The cross should be seen from a position immediately above it. 43 Which of the following methods can be used to determine the reaction rate of the following reaction? Cr 2 O 7 2(aq) + 14H+(aq) + 3C 2 O 4 2(aq) 6CO 2 (g) + 7H 2 O(l) + 2Cr3+(aq) (1) Measuring volume of CO 2 formed (2) Measuring time for pH change (3) Measuring time for the colour of the solution to change from orange to green A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 13
HKDSE Chemistry A Modern View Part IX Rate of Reaction
44 Some marble chips are mixed with excess dilute hydrochloric acid in a stoppered conical flask. The flask is placed on an electronic balance to determine its mass. The mass of the reaction mixture is measured at regular time intervals. Which of the following graphs represents the rate of the reaction? A.
B.
Reading of the balance
Reading of the balance
Time C.
Time D.
Reading of the balance
Reading of the balance
Time
Time
45 Which of the following reactions and methods of measuring reaction rate is INCORRECTLY matched? Reaction
Method of measuring reaction rate
A.
Fe3+(aq) + SCN(aq)
Measure the change in colour intensity of the reaction mixture
B.
C 4 H 6 O 4 (aq) + NaHCO 3 (aq)
Measure the change in pressure of reaction system by pressure sensor and data-logger
C.
H 2 O 2 (aq) + I(aq) + H+(aq)
Measure the change in mass of reaction mixture by electronic balance
D.
CH 3 COCH 3 (aq) + I 2( aq) + H+(aq)
Measure the change in concentration of I 2 (aq) by titration with sodium thiosulphate solution
46 In order to follow the progress of the reaction, Br 2 (aq) + HCOOH(aq) 2Br(aq) + 2H+(aq) + CO 2 (g) Which of the following techniques can be used? 14
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(1) Measuring the volume of gas produced (2) Measuring the loss of mass of the reaction mixture (3) Colorimetry A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 47 In order to follow the progress of the reaction, HCOOCH 3 (aq) + NaOH(aq) HCOONa+(aq) + CH 3 OH(aq) Which of the following techniques can be used? (1) Titrimetric analysis (2) Colorimetric analysis (3) Measuring the loss of mass of the reaction mixture A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 48 In order to follow the progress of the reaction, S 2 O 3 2(aq) + 2H+(aq) SO 2 (g) + S(s) + H 2 O(l) a paper with a black cross marked on it was placed below the beaker containing the reaction mixture. The cross gradually disappeared as the reaction proceeded. Which of the following is NOT a disadvantage of this technique? A. There is a significant error in determining whether the cross disappeared. B. The gas produced would affect the transmittance of light through the solution. C. The rate of reaction at a particular instant cannot be found. 1 D. The value of is just proportional time taken for disappearance of the cross to the average rate of reaction. 49 Hydrogen ion is used as a catalyst in esterification. Which of the following can be used to quench the reaction? A. Potassium permanganate 15
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B. C. D.
Hydrochloric acid Carbon dioxide Sodium hydroxide
50 A student is monitoring the progress of a chemical reaction by measuring the change in mass of the reaction mixture. The set-up is shown below: X hydrochloric acid Y
electronic balance Which of the following combinations is correct? X
Y
A.
Cotton wool plug
Magnesium carbonate
B.
Rubber plug
Magnesium chloride
C.
Cotton wool plug
Magnesium sulphate
D.
Rubber plug
Magnesium hydroxide
51 Which of the following methods can be used to quench a reaction? (1) Diluting the reaction mixture (2) Cooling the reaction mixture (3) Removing the reactant (4) Removing the product A. (1), (2) and (3) B. (1), (2) and (4) C. (1), (3) and (4) D. (2), (3) and (4) 52 Which of the following methods can monitor the rate of the reaction between Mg ribbon and HCl? (1) Measuring the change in mass of the reaction mixture 16
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(2) Measuring the change in colour intensity of the reaction mixture (3) Measuring the change in pressure of the reaction system A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 53 Which of the following reactions can be followed by measuring the change in mass? A. The reaction of vinegar and sodium hydroxide solution B. The decomposition of hydrogen peroxide into hydrogen and oxygen C. The reaction of magnesium ribbon and hydrochloric acid D. The reaction of acidified silver nitrate solution and sodium chloride solution 54 Which of the following reactions and methods of measuring reaction rate are NOT correctly matched? Reaction
Method of measuring reaction rate
A.
Hydrochloric acid and sodium thiosulphate solution
Measuring the time taken for the ‘blot out’ of a cross
B.
Methyl ethanoate and sodium hydroxide
Measuring the change in concentration of sodium hydroxide by titration with standard acid
C.
Magnesium ribbon and sulphuric acid
Measuring the change in pressure of reaction system by pressure sensor and data-logger
D.
Decomposition of hydrogen peroxide into hydrogen and oxygen
Measuring the change in volume of gas produced
55 The reaction rate of which of the following reactions can be measured using a colorimeter? A. Dissolving eggshells in sulphuric acid solution B. The reaction of sulphur dioxide and bromine water C. The reaction of ethyl propanoate and sodium hydroxide D. The reaction of silver and nitric acid
17
HKDSE Chemistry A Modern View Part IX Rate of Reaction
56 After the addition of marble chips to an excess of dilute hydrochloric acid in a conical flask, each of the following was measured and plotted against time on a graph.
Time (min) If the reaction was complete in 2.5 minutes, which of the following, when plotted against time, would give a graph like the one shown above? A. Total mass of the conical flask and its contents B. Volume of carbon dioxide produced C. pH of the solution D. Temperature of the solution 57 In which of the following reactions the rate CANNOT be measured by the set-up shown?
collected gas
gas syringe
dilute hydrochloric acid magnesium ribbon A. B. C. D.
ZnCO 3 + HCl Zn + H 2 SO 4 ZnO + HNO 3 Zn + CH 3 COOH
58 Which of the following shows the correct sequence of results of measuring rate of reaction between sodium thiosulphate solution and dilute hydrochloric acid? (The diagrams show the top view of the solution in a beaker putting on top of a marked 18
HKDSE Chemistry A Modern View Part IX Rate of Reaction
cross.) A.
B.
C.
D.
59 Which of the following sets of apparatus could be used to measure the speed of the reaction between marble chips and dilute nitric acid? (1) boiling tube
dilute nitric acid marble chips
water
(2)
dilute nitric acid electronic balance
19
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(3)
rubber connecting tubing
gas syringe dilute nitric acid marble chips A. B. C. D.
(1) only (2) only (1) and (3) only (2) and (3) only
60 A test tube containing dilute sulphuric acid was placed in a flask containing excess zinc granules. The flask was then tilted so that the acid was poured out of the test tube and completely covered the zinc granules. The flask was re-weighed at intervals from the start of the reaction. Which of the following diagrams is correct?
dilute sulphuric acid zinc granules A.
B.
Mass of flask
Time
Mass of flask
Time
20
HKDSE Chemistry A Modern View Part IX Rate of Reaction
C.
D.
Mass of flask
Mass of flask
Time
Time
61 Which of the following methods is most suitable for measuring the reaction rate of the following chemical reaction? S 2 O 3 2(aq) + 2H+(aq) SO 2 (g) + H 2 O(l) + S(s) A. Measuring the time taken to reach an easily seen stage. e.g. to blot out a marked cross. B. Measuring the change in volume of H 2 O(l) with time. C. Measuring the change in volume of SO 2 (g) formed with time. D. Measuring the change in pressure of the reaction system with time. 62 In order to follow the progress of the reaction, Br 2 (aq) + HCOOH(aq) 2Br(aq) + 2H+(aq) + CO 2 (g) Which of the following techniques can be adopted? (1) Measuring the volume of gas produced (2) Measuring the loss of mass of the reaction mixture (3) Colorimetric analysis A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 63 In order to follow the progress of the reaction, HCOOCH 3 (aq) + NaOH(aq) HCOONa(aq) + CH 3 OH(aq) Which of the following techniques can be adopted? (1) Titrimetric analysis (2) Colorimetric analysis (3) Measuring the loss of mass of the reaction mixture A. (1) only 21
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B. C. D.
(2) only (1) and (3) only (2) and (3) only
64 Which of the following methods are possible to quench a reaction mixture? (1) Cooling the reaction mixture in ice (2) Removing one of the reactants (3) Diluting the reaction mixture A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 65 In order to follow the progress of the following reaction: S 2 O 3 2(aq) + 2H+(aq) SO 2 (g) + S(s) + H 2 O(l), a white tile with a cross marked on it was placed below the beaker of reaction mixture. The cross gradually disappeared as the reaction went on. Which of the following is NOT a disadvantage of this technique? A. There is a significant error in determining whether the cross has disappeared. B. It is inconvenient to set up the apparatus. C. The rate of reaction at a particular instant cannot be found. 1 D. The value of is just proportional time taken for disappearance of the cross to the average rate. Each question below consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table: A.
Both statements are true and the 2nd statement is a correct explanation of the 1st statement. B. Both statements are true and the 2nd statement is NOT a correct explanation of the 1st statement. C. The 1st statement is false but the 2nd statement is true. D. Both statements are false. 22
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Section 38.1 66 Zn reacts with water faster than Cu.
Zn is more reactive than Cu.
67 There is no air inside a refrigerator.
Food will go bad slower in a refrigerator.
Section 38.2 68 The initial rates of most reactions are the highest.
The initial rate of a reaction is the instantaneous rate at t = 0.
69 The instantaneous rate of a reaction is calculated from the slope of the tangent to the rate curve at t = 0.
The rate curve of most reactions is the steepest at first and becomes less steep with time.
70 Instantaneous rate of reaction is always higher than the average rate of reaction.
Average rate of reaction can be calculated from a rate curve.
Section 38.3 71 Ice water is usually used to quench a reaction.
Ice water dilutes the reaction mixture.
72 The rate of reaction between sodium thiosulphate and dilute hydrochloric acid is measured by the time taken for the ‘blot out’ of the cross marked on the white tile.
The time taken for the ‘blot out’ of the cross is inversely proportional to the average rate of formation of sulphur.
23
HKDSE Chemistry A Modern View Part IX Rate of Reaction
73 Sodium carbonate can be used to quench the reaction between propanone and iodine.
An acid is used as the catalyst in the reaction between propanone and iodine.
Chemistry: Chapter 39 Factors affecting rate of reaction Sections 39.139.2 74 Which of the following statements concerning the collision theory are correct? (1) Reactant particles must collide to trigger a reaction. (2) Products can only be formed if the collision is in the right orientation, regardless of the speed of the reactant particles. (3) Only a small fraction of collisions is classified as effective collisions. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 75 According to the collision theory, which of the following is/are essential for a chemical reaction to occur? (1) Collision of reactant particles. (2) Possession of adequate kinetic energy by reactant particles. (3) Possession of adequate kinetic energy by product particles. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 76 An increase in the number of effective collisions per unit time implies A. an increase in concentration of reactants. B. an increase in temperature. C. an increase in surface area of reactants. D. an increase in reaction rate. 77 24
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Which of the following is/are important in determining whether a reaction occurs? (1) Size of the molecules (2) Energy of the molecules (3) Orientation of the molecules A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) Section 39.3 78 A fixed mass of magnesium strips reacts with excess dilute sulphuric acid of different concentrations. Which of the following statements is/are correct? (1) For the most concentrated acid, the rate curve of production of H 2 gas gives the largest slope initially. (2) For the most concentrated acid, the reaction takes the longest time to complete. (3) For the most concentrated acid, the volume of H 2 gas produced is the largest. A. B. C. D.
(1) only (2) only (1) and (3) only (2) and (3) only
79 In the graphs below, curve (i) was obtained when 3 g of zinc granules was reacted with excess 2.0 M hydrochloric acid. Curves (ii) and (iii) were obtained after making changes to the acid. Curve (ii): Excess 1.0 M nitric acid Curve (iii): Excess 1.5 M sulphuric acid Which of the following graphs matches the rate curves (i), (ii) and (iii) correctly? A.
Volume of H 2 (g)
ii i iii
Time
25
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B.
Volume of H 2 (g)
ii i iii
Time C.
Volume iii of H 2 (g) i ii
Time D.
Volume of H 2 (g)
iii i ii
Time
80 Consider the following equation of rusting of iron: 4Fe(s) + 3O 2 (g) + 2nH 2 O(l) 2Fe 2 O 3 • nH 2 O(s) Which of the following statements correctly explains that a coating of oil can slow down the rusting of iron gears of a bicycle? A. The oil cools down the iron gears. B. The oil prevents oxygen from reaching the iron gears, so the concentration of oxygen in the rusting reaction is decreased. C. The oil decreases the surface area of iron gears. D. The oil is an ‘anti-catalyst’. 81 When the concentration of a reactant is increased, which of the following concerning the reactant particles will NOT occur? 26
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(1) There will be a larger number of collisions. (2) Reactant particles will have a greater amount of average kinetic energy. (3) There will be a larger fraction of effective collisions. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 82 An experiment was carried out to investigate the relationship between temperature and rate of reaction for the following reaction. S 2 O 3 2(aq) + 2H+(aq) S(s) + SO 2 (g) + H 2 O(l) The resultant solution became cloudy as sulphur was formed in the reaction. A paper with a black cross marked on it was placed below the beaker containing the reaction mixture. At 298 K, time taken for the ‘blot out’ of the cross was 130 seconds. At 308 K, the time was 66 seconds. Which of the following conclusions can be obtained? A. Rate increases by around two times when the temperature increases by 10 K. B. Rate increases by around four times as the temperature increases by 10 K. C. Rate decreases by roughly a half as the temperature increases by 10 K. D. Rate decreases by roughly one fourth as the temperature increases by 10 K. 83 Zinc metal reacts with excess 1.0 M HCl according to the following equation: Zn(s) + 2H+(aq) Zn2+(aq) + H 2 (g) Which of the following changes will increase the rate of evolution of H 2 (g)? (1) Using zinc dust instead of chunks. (2) Using 200 cm3 of 1.0 M HCl in place of 100 cm3. (3) Using 2.0 M HCl instead of 1.0 M HCl. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 84 For a given reaction, why does the rate of reaction increase when the concentrations of the reactants are increased? A. The frequency of the molecular collisions increases. 27
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B. C. D.
The surface area of molecules increases. The average kinetic energy of the molecules increases. The amount of the reactants increases.
85 Consider the reaction of excess dilute hydrochloric acid and magnesium ribbon, which of the following parameters is/are NOT changed upon changes in the concentration of the hydrochloric acid, given other factors are kept constant? (1) The total heat energy released from the reaction mixture (2) The time taken for the reaction to complete (3) The total volume of gas collected A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 86 Which of the following reactants will give the highest reaction rate when reacting with 1 g of NaOH(s)? A. 90 cm3 of 0.2 M H 2 SO 4 B. C. D.
80 cm3 of 0.3 M H 2 SO 4 60 cm3 of 0.4 M HCl 40 cm3 of 0.5 M HCl
87 Arrange the following reaction rates in descending order. (1) Reaction between 3.0 g of magnesium granules and 1.0 M of CH 3 COOH at room temperature. (2) Reaction between 3.0 g of magnesium powder and 1.0 M of HCl at a warm water bath. (3) Reaction between 3.0 g of magnesium powder and 0.6 M of H 2 SO 4 at a warm water bath. (4) Reaction between 2.0 g of magnesium granules and 0.9 M of CH 3 COOH at room temperature. A. (1) > (3) > (4) > (2) B. (2) > (3) > (4) > (1) C. (2) > (4) > (1) > (3) D. (3) > (2) > (1) > (4) 28
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Section 39.4 88 Consider the following reaction: S 2 O 3 2(aq) + 2H+(aq) SO 2 (g) + H 2 O(l) + S(s) A white tile with a black cross marked on it was placed under a beaker. 50.0 cm3 of 0.10 M sodium thiosulphate solution and 10.0 cm3 of 1.0 M hydrochloric acid were mixed in the beaker. Sulphur was produced and the cross was blocked. Which of the following changes can make the cross disappear in a shorter time? (1) Warm the reagents before the reaction. (2) Use 100 cm3 of 0.10 M sodium thiosulphate solution instead. (3) Use 20.0 cm3 of 2.0 M hydrochloric acid instead. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 89 An increase in temperature of the reactants increases the rate of reaction. Which of the following statements explains this situation correctly? A. Heat energy causes an increase in concentration of the reactants. B. Heat energy causes an increase in size of the molecules. C. Heat energy causes a decrease in energy required for the reaction to occur. D.
Heat energy causes the reactant particles to move faster.
90 Sodium hydroxide reacts with acids. Which of the following solutions would give the highest initial rate? A. B. C. D.
60 cm3 of 1.5 M NaOH(aq) and 60 cm3 of 1.5 M HCl(aq) at 30C. 50 cm3 of 2.0 M NaOH(aq) and 50 cm3 of 2.0 M HCl(aq) at 20C. 20 cm3 of 2.0 M NaOH(aq) and 20 cm3 of 1.5 M H 2 SO 4 (aq) at 30C. 40 cm3 of 1.5 M NaOH(aq) and 40 cm3 of 2.0 M CH 3 COOH(aq) at 25C.
91 Na 2 S 2 O 3 (aq) + H 2 SO 4 (aq) Na 2 SO 4 (aq) + H 2 O(l) + SO 2 (g) + S(s) Which of the following reactions has the shortest time for ‘blot out’ at room temperature and pressure? Na 2 S 2 O 3
H 2 SO 4
H2O 29
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Volume (cm3)
Concentration
Concentration
(mol dm )
Volume (cm3)
(mol dm )
Volume (cm3)
A.
5
0.15
10
0.15
0
B.
5
0.20
10
0.10
5
C.
10
0.10
10
0.10
0
D.
5
0.20
5
0.20
10
3
3
92 When temperature is increased, which of the following concerning collisions of reactant particles will occur? (1) There will be a larger number of effective collisions. (2) There will be a larger number of ineffective collisions. (3) Reactant particles will have a higher average kinetic energy. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 93 When the surface area of a solid reactant is increased, which of the following concerning the reactant particles will NOT occur? (1) There will be a larger number of collisions. (2) Reactant particles will have a greater amount of average kinetic energy. (3) There will be a larger fraction of effective collisions. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 94 Powdering a solid reactant can A. increase the chance of collision between reactant particles. B. reduce the energy required for reaction to occur. C. increase the concentration of the reactant. D. convert the reactant into a catalyst. 95 A small increase in temperature often produces a large increase in the rate of a 30
HKDSE Chemistry A Modern View Part IX Rate of Reaction
chemical reaction because it A. decreases the size of the reactant particles. B. increases the effectiveness of the collisions between the reactant molecules. C. decreases the number of collisions per second between the reactant molecules. D. decreases the volume of the solution, altering the concentrations of the reactants. 96 The rates of many chemical reactions double when there is a ten-degree rise in temperature. Which of the following factors DOES NOT contribute to this change in rate with increasing temperature? A. The average kinetic energy of the reactant species. B. The number of collisions in a given time. C. The number of very energetic species. D. The moving path of the reactant particles. 97 Which of the following statements correctly explains the effect of increase in temperature of reactants on reaction rate? A. Increase in temperature raises the potential energy of the reactant particles. B. Increase in temperature reduces the energy difference between the reactants and products. C. Increase in temperature raises the average kinetic energy of the reactant particles. D. Increase in temperature reduces the contribution from orientation factor. 98 A chemical reaction takes place inside a glow stick. The higher the temperature, the brighter is the glow stick. Which of the following descriptions about the glowing time at a higher temperature is correct? A. Longer B. Shorter C. Unchanged D. Uncertain 99 Superheated water (boiling point > 100C) can make cooking faster. Which of the 31
HKDSE Chemistry A Modern View Part IX Rate of Reaction
following methods can be used to prepare the superheated water? A. Overheat the water. B. Add table salt to the water. C. Increase the pressure. D. Use distilled water. Section 39.5 100 Which of the following factors DOES NOT affect the rate of reaction? A. Surface area of the solid reactant B. Molar mass of the reactant C. Temperature of the reaction system D. Concentration of the reactant 101 Which of the following factors affect(s) the rate of reaction between a solid reactant and a liquid reactant? (1) Molar mass of the solid reactant (2) Concentration of the liquid reactant (3) Surface area of the solid reactant A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 102 Which of the following is the reason for the fact that antacids have to be chewed before swallowing? A. A catalyst is added by saliva. B. The temperature of the antacid is increased. C. The surface area of the antacids is increased. D. The concentration of the antacids is increased. 103 Which of the following factors can speed up reactions in industrial chemical production involving gaseous reactants? (1) Temperature (2) Pressure 32
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(3) Catalyst A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
104 Consider the reaction between solid calcium carbonate and aqueous hydrochloric acid. Which of the following conditions can be increased to speed up the reaction? (1) Concentration of HCl (2) Surface area of the CaCO 3 particles (3) Temperature A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
Mass
105 Excess magnesium was added to a beaker of aqueous hydrochloric acid on a balance. A graph of the mass of the beaker and contents was plotted against time (curve 1).
1 2 Time Which of the following changes in the experiment could give curve 2? (1) The same mass of magnesium but in smaller pieces (2) The same volume of a more concentrated solution of hydrochloric acid (3) A lower temperature A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 33
HKDSE Chemistry A Modern View Part IX Rate of Reaction
106 Which of the following changes CANNOT increase the rate of the reaction of chlorine gas and a liquid hydrocarbon? A. Use UV light to dissociate the Cl 2 . B. Increase temperature at constant pressure. C. Use chlorine gas of higher concentration. D. Increase the pressure by adding helium gas. 107 Which of the following factors determine(s) the rate of a chemical reaction? (1) Molar mass of reactants added (2) Average kinetic energy of reactant particles (3) Surface area of solid reactants A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 108 Which of the following statements correctly explains the higher reaction rate when using the same amount of powdered limestone instead of lumps of limestone to react with hydrochloric acid? A. Particles on the surface of the limestone are more activated for reactions to occur, so increase in surface area increases the rate. B. Particles on the surface of the limestone are more properly orientated so that increase in surface area increases the rate. C. The hydrogen ions are less reactive towards the particles inside the solid reactant so that increase in surface area increases the rate. D. The hydrogen ions can only collide with the particles on the surface of the solid reactant so that increase in surface area increases the rate. 109 Which of the following statements explains correctly why antacids should be well chewed before swallowing? A. Gritted by teeth makes antacids hotter, so it will be more reactive. B. The enzyme of the saliva can activate the antacids. C. Chewing compresses the antacid molecules, so its concentration increases. 34
HKDSE Chemistry A Modern View Part IX Rate of Reaction
D.
Chewing grinds the tablets into small pieces, so the surface area of antacids increases.
110 Which of the following processes CANNOT be employed to increase the reaction rate? CaCO 3 (s) + 2HCl(aq) CaCl 2 (aq) + H 2 O(l) + CO 2 (g) A. Use the same concentration of H 2 SO 4 . B. Heat the reaction mixture. C. Grind the calcium carbonate. D. Carry out the reaction in a smaller container. Section 39.6 111 The following set-up is used to investigate the decomposition of hydrogen peroxide. 2H 2 O 2 (aq) 2H 2 O(l) + O 2 (g) stopwatch cotton wool a small amount of solid MnO 2
measured volume of standard H 2 O 2 (aq) electronic balance
A graph of the mass of the reaction mixture against time was plotted. Which of the following curves would be obtained? Mass of reaction mixture
A B C
D Time
35
HKDSE Chemistry A Modern View Part IX Rate of Reaction
112 Which of the following statements concerning a catalyst MUST be correct? A. The rate of reaction is increased. B. A catalyst remains chemically and physically unchanged after a reaction. C. A catalyst is neither a reactant nor a product. D. A catalyst can operate under any conditions. 113 P and Q are mixed together and they have the following reactions: P+QR Q+RP+S+T Which of the following statements is correct? A. P is a catalyst. B. Q is a catalyst. C. R is a catalyst. D.
The overall reaction is 2Q + R S + T.
114 Catalyst is an important chemical that can increase the reaction rate greatly. Which of the following reactions and catalysts are correctly matched? Reaction
Catalyst
(1) 2SO 2 (g) + O 2 (g) (2) N 2 (g) + 3H 2 (g)
2SO 3 (g) 2NH 3 (g)
(3) 2H 2 O 2 (aq) 2H 2 O(l) + O 2 (g) A. B. C. D.
Pt Fe MnO 2
(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)
115 Which of the following about rate of reaction is correct? A. The fraction of effective collisions does not depend on temperature. B. The concentration of a solid reactant increases when its surface area increases. C. The rate of reaction cannot be decreased by a catalyst. D. The rate of reaction has no relationship with the enthalpy change of reaction. 36
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Reaction rate
116 Curves with the shape shown below are often observed for reactions involving catalysts.
Concentration of reactant The level portion of the curve is best attributed to the fact that A. product is no longer being formed. B. the reaction is complete. C. all the catalytic sites are occupied. D. the catalyst is used up. 117 For an exothermic reaction in which 2 moles of gaseous reactants are converted to 3 moles of gaseous products, which of the following changes will lower the reaction rate? A. Decreasing the volume B. Adding more reactants C. Decreasing the pressure D. Using a steam bath 118 Which of the following statements about the collision theory is/are INCORRECT? (1) All reactant particles are moving at equal speed under the same temperature and pressure. (2) Only a small fraction of collisions can lead to the formation of products. (3) Products are formed when the reactant particles collide at high speed and both particles have the reactive sites for reaction. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 37
HKDSE Chemistry A Modern View Part IX Rate of Reaction
119 Which of the following statements concerning a catalyst is INCORRECT? A. A catalyst can increase the reaction rate. B. A catalyst is neither a reactant nor a product of a reaction. C. A catalyst can increase the frequency of collisions between reactant particles. D. A catalyst can be regenerated at the end of a reaction. Section 39.7 120 Which of the following conditions is/are used in Contact process? (1) A high temperature of 450C (2) Iron as the catalyst (3) A high pressure of 250 atm A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 121 Yeast is commonly used in bakery. Which of the following statements concerning the reaction that involves yeast is/are correct? (1) Yeast contains an enzyme called zymase as the catalyst. (2) The enzyme breaks down starch into ethanol and carbon dioxide. (3) Carbon dioxide produced in the reaction makes the bread ‘raise’. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 122 Why can the browning of fruits be slowed down if they are put in vinegar? A. Vinegar prevents O 2 to come into contact with the fruits. B. The enzymes in cells which speed up the reaction leading to the formation of brown substance are denatured. C. Brown substances are indeed the oxides of iron. Thus, acid neutralizes and dissolves the oxides. 38
HKDSE Chemistry A Modern View Part IX Rate of Reaction
D.
Brown substances dissolve in vinegar.
123 Which of the following statements explains why catalysts are often used in chemical reactions? A. Catalysts increase the rate of reactions. B. Catalysts increase the yield of products of reactions. C. Catalysts increase the purity of products of reactions. D. Catalysts decrease the amount of reactants. 124 Which of the following is NOT a proper reason for the application of catalysts in chemical industries? A. To save time. B. To reduce the cost of production. C. To increase the yield of products. D. To save the use of fuel. 125 Contact process is an important step in the manufacture of sulphuric acid. What is the catalyst used in this process? A. V 2 O 2 B. C. D.
V2O3 V2O5 VO 3
126 Which of the following processes requires the presence of a catalyst? (1) Alkaline hydrolysis of ester (2) Fermentation (3) Oxidation of propanone by iodine (4) Browning of fruits A. (1), (2) and (3) B. (1), (2) and (4) C. (1), (3) and (4) D. (2), (3) and (4) Each question below consists of two separate statements. Decide whether each of 39
HKDSE Chemistry A Modern View Part IX Rate of Reaction
the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table: A.
Both statements are true and the 2nd statement is a correct explanation of the 1st statement. B. Both statements are true and the 2nd statement is NOT a correct explanation of the 1st statement. C. The 1st statement is false but the 2nd statement is true. D. Both statements are false.
Sections 39.139.3 127 The rate of reaction at the start of most reactions is the highest.
The concentrations of reactants at the start of most reactions are the highest.
128 Reaction rate depends on the concentration of reactants for most reactions.
Increasing the concentration of the excess reactant will increase the reaction rate for most reactions.
Section 39.4 129 When the temperature of a reaction is increased, the reaction rate increases.
An increase in temperature raises the average kinetic energy of the reactant particles.
130 Effervescence lasts longer when 3 g of calcium carbonate is put into excess hydrochloric acid at a higher temperature.
The reaction rate is increased if the temperature is raised.
Sections 39.539.6 131 Catalysts can increase the rate of a chemical reaction.
A catalyst is chemically unchanged at the end of a reaction.
40
HKDSE Chemistry A Modern View Part IX Rate of Reaction
132 Although a catalyst will not be used up in a reaction, it is regarded as a reactant.
Reaction time is always reduced when a catalyst is used in a reaction.
133 Manganese(IV) oxide (MnO 2 ) can be regenerated from the reaction mixture of hydrogen peroxide.
Manganese(IV) oxide (MnO 2 ) is the catalyst for the decomposition of hydrogen peroxide.
134 A catalyst can always increase the rate of reaction.
A catalyst can increase the number of effective collisions.
Section 39.7 135 It is generally better to use powdered catalyst to catalyze a reaction.
Iron is used as the catalyst in Haber process.
136 Haber process is carried out at 450C and 1 atm.
One mole of nitrogen reacts with three moles of hydrogen in Haber process.
Chemistry: Chapter 40 Molar volume of gases at room temperature and pressure (r.t.p.) Section 40.1 137 Which of the following gases has the highest density at r.t.p.? A. Chlorine B. Ammonia C. Propane D. Carbon dioxide 138 41
HKDSE Chemistry A Modern View Part IX Rate of Reaction
Consider the following chemical reaction: 2NaN 3 (s) 2Na(s) + 3N 2 (g) It was found that 0.524 g of NaN 3 decomposes to form 0.290 dm3 of nitrogen gas at a certain temperature and pressure. What is the molar volume of N 2 at that temperature and pressure? A. B. C. D.
22.8 dm3 mol1 23.5 dm3 mol1 24.0 dm3 mol1 25.3 dm3 mol1
Section 40.2 139 3.0 dm3 of sulphur dioxide gas, SO 2 , and 2.0 dm3 of oxygen gas, O 2 , are reacted at a certain temperature and pressure. What is the volume of gaseous sulphur trioxide, SO 3 , that can be produced at this temperature and pressure? A. B. C. D.
1.0 dm3 1.5 dm3 2.0 dm3 3.0 dm3
140 An important reaction in the production of nitrogen fertilizers is 4NH 3 (g) + 5O 2 (g) 4NO(g) + 6H 2 O(g) At constant temperature and pressure, what is the maximum volume of NO that can be produced from 14.0 dm3 of NH 3 and 16.0 dm3 of O 2 ? A. 12.8 dm3 B. 14.0 dm3 C. 17.5 dm3 D. 20.0 dm3 141 What volume of oxygen gas (O 2 ), measured at 0C and 1 atm, is needed to completely burn 1.0 dm3 of propane (C 3 H 8 ) measured at the same conditions? A. 10 dm3 B. 7.0 dm3 C. 6.0 dm3 D. 5.0 dm3
42
HKDSE Chemistry A Modern View Part IX Rate of Reaction
142 Assume that 0.10 dm3 of N 2 and 0.18 dm3 of H 2 , both at 50 atm and 450C, are reacted to form NH 3 . If the reaction goes to completion, identify the reagent that is in excess and determine the volume remained at the same temperature and pressure. A. H 2 , 0.02 dm3 B. H 2 , 0.08 dm3 C. N 2 , 0.01 dm3 D. N 2 , 0.04 dm3 143 At a certain temperature and pressure, 3.0 dm3 of sulphur dioxide is reacted with 2.0 dm3 of oxygen according to the equation below. 2SO 2 (g) + O 2 (g) 2SO 3 (g) What volume of sulphur trioxide (in dm3) was formed at the same temperature and pressure? A. 5.0 B. 4.0 C. 3.0 D. 2.0 144 What is the volume of hydrogen evolved when 0.654 g of zinc was reacted with excess dilute hydrochloric acid at r.t.p.? A. 120 cm3 B. C. D.
200 cm3 240 cm3 360 cm3
145 What volume of oxygen at r.t.p. is required for the complete combustion of 150 cm3 of propane? A. 751 cm3 B. 802 cm3 C. 857 cm3 D. 900 cm3 146 At a certain temperature and pressure, what is the volume of steam formed from the 43
HKDSE Chemistry A Modern View Part IX Rate of Reaction
reaction 4NH 3 (g) + 5O 2 (g) 4NO(g) + 6H 2 O(g) when 100 cm3 of ammonia is reacted with excess oxygen at the same temperature and pressure? A. 100 cm3 B. 125 cm3 C. 150 cm3 D. 175 cm3 147 Butene reacts with oxygen according to the equation, C 4 H 8 (g) + 6O 2 (g) 4CO 2 (g) + 4H 2 O(l). At a certain temperature and pressure, 35.0 cm3 of butene was mixed with 300 cm3 of oxygen and the reaction was initiated by a spark. Assuming complete combustion, what is the total volume of gas at the end of the reaction? A. 90 cm3 B. 140 cm3 C. 230 cm3 D. 320 cm3 148 Which of the following pairs of gases have the same number of atoms at the same temperature and pressure? A.
200 cm3 of steam
200 cm3 of ammonia
B.
1 dm3 of carbon dioxide
1 dm3 of sulphur trioxide
C.
100 cm3 of methane
500 cm3 of neon
D.
50 cm3 of hydrogen chloride
50 cm3 of hydrogen sulphide
149 30 cm3 of chlorine is mixed with 70 cm3 of hydrogen in a test tube with a stopper. Then the test tube is allowed to expose to sunlight for half an hour. In the presence of sunlight, chlorine reacts with hydrogen to give hydrogen chloride. What is the volume of hydrogen chloride produced? (Assume that all the volumes are measured at r.t.p.) A. 30 cm3 B. C. D.
40 cm3 60 cm3 140 cm3
150 If two moles of sulphur dioxide are oxidized to sulphur trioxide by air, what is the 44
HKDSE Chemistry A Modern View Part IX Rate of Reaction
minimum volume of air required at r.t.p.? (Assuming air contains 20% of oxygen by volume and the reaction is forced to complete, so that all sulphur dioxide and oxygen are converted to SO 3 ; molar volume of any gas at r.t.p. = 24.0 dm3 mol1) A. 80 dm3 B. 100 dm3 C. 120 dm3 D. 140 dm3 151 What is the volume of oxygen required for the complete combustion of 50 cm3 of methane, CH 4 at r.t.p.? A. 100 cm3 B. 50 cm3 C. 25 cm3 D. 10 cm3 152 What is the volume of oxygen required for the complete combustion of a mixture of 50 cm3 of methane, CH 4 , and 25 cm3 of carbon monoxide, CO at r.t.p.? (Molar volume of any gas at r.t.p. = 24 dm3 mol1) A. 75 cm3 B. 100 cm3 C. 112.5 cm3 D. 150 cm3 153 Avogadro’s Law states that A. one mole of substance contains 6.02 × 1023 units of that substance. B. equal volumes of gases contain the same number of molecules at the same temperature and pressure. C. gases occupy the same volume at any temperature and pressure. D. one mole of gas occupies 24.0 dm3 at room temperature and pressure. 154 Which of the following is the correct sequence of the volumes occupied by 1 mol of the following gases under r.t.p. in ascending order? (1) Sulphur dioxide 45
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(2) Oxygen (3) Carbon dioxide A. (1), (2), (3) B. (1), (3), (2) C. (2), (3), (1) D. They occupy the same volume. 155 Consider the following chemical reaction: N 2 (g) + 3H 2 (g) 2NH 3 (g) If the reaction goes to completion, what volume of hydrogen gas (H 2 ) is required to produce 20.0 cm3 of ammonia (NH 3 ) at r.t.p.? A. 6.67 cm3 B. 10.0 cm3 C. 20.0 cm3 D. 30.0 cm3 156 Consider the following chemical reaction: S(s) + O 2 (g) SO 2 (g) What is the amount of sulphur needed to produce 10.0 cm3 of SO 2 at r.t.p.? A. B. C. D.
4.17 × 104 mol 4.17 × 102 mol 2.40 × 103 mol 2.40 × 102 mol
157 20 cm3 of ethane (C 2 H 6 ) are burned with 95 cm3 of oxygen to give carbon dioxide and water as the only products. What is volume of oxygen unreacted? (All volumes are measured at r.t.p.) 2C 2 H 6 (g) + 7O 2 (g) 4CO 2 (g) + 6H 2 O(l) A. 20 cm3 B. 25 cm3 C. 55 cm3 D. 75 cm3 158 20 cm3 of chlorine reacts with 40 cm3 of oxygen to form 40 cm3 of a gaseous oxide of 46
HKDSE Chemistry A Modern View Part IX Rate of Reaction
chlorine. What is the molecular formula of this oxide? (All volumes are measured at r.t.p.) A. ClO B. Cl 2 O C. ClO 2 D. Cl 2 O 3 159 When excess sulphur is burnt with 1 mole of O 2 to form sulphur dioxide at r.t.p., which of the following statements are correct? (1) Mole ratio of SO 2 : O 2 equals 1 : 1. (2) Volume of SO 2 formed equals 24.0 dm3. (3) Volume of O 2 consumed equals 24.0 dm3. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 160 What is the volume of 3 moles of CH 4 (g) at r.t.p.? A. 7.2 dm3 B. C. D.
480 dm3 72 000 cm3 48 000 cm3
161 What is the number of moles of 300 cm3 of ethane at room temperature and pressure? A. 0.125 mol B. 0.0125 mol C. 0.0800 mol D. 0.800 mol 162 What is the volume of 2.80 moles of hydrogen chloride gas at room temperature and pressure? A. 67.2 dm3 B. 102 dm3 C. 0.672 dm3 47
HKDSE Chemistry A Modern View Part IX Rate of Reaction
D.
8.57 dm3
163 Which of the following statements is correct? A. Under stated temperature and pressure, the volume of a gas is determined by the size of the gas molecules. B. Under stated temperature and pressure, the volume of a gas is determined by the quantity of the gas molecules. C. Under stated temperature and pressure, different gases with equal volume have different number of molecules. D. Under stated temperature and pressure, 1 mole of gas molecules occupies a volume of 24.0 dm3. 164 Hydrogen can be ignited in chlorine gas to form a white fume, hydrogen chloride. If 250 cm3 of HCl was found to be the only remaining species in the reaction, what volumes of hydrogen and chlorine were reacted at room temperature and pressure? Volume of H 2 (cm3)
Volume of Cl 2 (cm3)
A.
250
250
B.
250
125
C.
125
125
D.
125
250
165 The molar volume of different gases at r.t.p. deviates from 24.0 dm3 mol1. Which of the following is the main reason behind? A. Intermolecular interaction B. Volume of the gas molecule C. Experimental inability D. Molar mass of the gas molecule 166 A hypothetical reaction 2N x O y (g) xN 2 (g) + yO 2 (g) goes to completion upon heating. If originally there is only N x O y which contains 8.4 × 1023 atoms, and finally there are 2.4 × 1023 nitrogen atoms, which of the following can be the molecular formula of the compound N x O y ? A. N 2 O 48
HKDSE Chemistry A Modern View Part IX Rate of Reaction
B. C. D.
NO 2 N2O4 N 4 O 10
167 Which of the following gases has the greatest number of atoms under r.t.p.? A. 18 dm3 of ammonia B. 32 dm3 of helium C. 6.0 dm3 of methane D. 8.0 dm3 of sulphur trioxide 168 What is the number of moles of atoms in 500 cm3 of CH 4 at r.t.p.? A. 1.04 mol B. 0.104 mol C. 0.0104 mol D. 10.4 mol 169 What is the number of molecules in 305 cm3 of O 2 (g) at r.t.p.? A. B. C. D
3.83 × 1021 7.64 × 1022 1.53 × 1022 7.65 × 1021
170 Which of the following equations represents the calculation of molar volume? A.
molarity molar mass
B.
molar mass density
C. D.
concentration × number of moles total volume Avogadro constant
Section 40.3 171 What is the volume of 4.3 g of ammonia gas at r.t.p.? 49
HKDSE Chemistry A Modern View Part IX Rate of Reaction
A. B. C. D.
0.250 dm3 6.07 dm3 250 dm3 607 dm3
172 0.22 g of carbon dioxide occupies a volume of 120 cm3 at r.t.p. What is the molar mass of carbon dioxide? A. B. C. D.
43.4 g mol1 43.6 g mol1 43.8 g mol1 44.0 g mol1
173 1 dm3 of a certain gas has a mass of 1.33 g at r.t.p. What is this gas? A. Nitrogen B. Oxygen C. Carbon monoxide D. Methane 174 0.8 g of magnesium carbonate reacts with 100 cm3 of 1.0 M sulphuric acid at r.t.p. What is the volume of carbon dioxide produced? A. 2.28 dm3 B. 4.56 dm3 C. 114 cm3 D. 228 cm3 175 Potassium chlorate (KClO 3 ) is often used in secondary school laboratories to produce oxygen gas. When it is heated in contact with a catalyst, typically manganese(IV) dioxide, it will decompose readily to give oxygen gas. What is the volume of oxygen obtained at r.t.p. if 5.0 g of potassium chlorate is decomposed? A. 1.35 dm3 B. 1.47 dm3 C. 1.96 cm3 D. 2.94 cm3 MnO 2 50
HKDSE Chemistry A Modern View Part IX Rate of Reaction
176 Limestone decomposes upon strong heating. What is the mass of limestone needed to produce 6.0 dm3 of carbon dioxide at r.t.p.? (Assume the percentage by mass of CaCO 3 in limestone = 90%) A. 22.5 g B. 25.0 g C. 27.8 g D. 30.2 g 177 Equal masses of O 2 and N 2 are reacted according to the equation: O 2 (g) + N 2 (g) 2NO(g) Which of the following statements is true? A. O 2 is left at the end of the reaction. B. N 2 is left at the end of the reaction. C. All of the O 2 and N 2 react and neither is in excess. D. Equal mass of NO is produced. 178 A 0.10 g sample of zinc is added to excess hydrochloric acid. When the reaction is complete, what is the volume of gas, in cm3, that is evolved at r.t.p.? A. 74.0 B. 36.7 C. 34.2 D. 68.5 179 Dinitrogen oxide (N 2 O), which is commonly called laughing gas, can be made by heating ammonium nitrate (NH 4 NO 3 ) alone, with water as the only side product. Calculate the mass of ammonium nitrate needed to produce 15.0 dm3 of laughing gas at r.t.p. A. 20.0 g B. 30.0 g C. 40.0 g D. 50.0 g 180 What volume of 0.5 M hydrochloric acid is required to neutralize excess anhydrous 51
HKDSE Chemistry A Modern View Part IX Rate of Reaction
sodium carbonate, with 1200 cm3 of carbon dioxide produced at r.t.p.? A. 100 cm3 B. 200 cm3 C. 250 cm3 D. 300 cm3 181 Methane can be synthesized from the hydrolysis of aluminium carbide, Al 4 C 3 (s) + 12H 2 O(l) 3CH 4 (g) + 4Al(OH) 3 (s). What volume of methane at r.t.p. can be obtained from 0.48 g of aluminum carbide with excess water? A. 0.240 dm3 B. 0.300 dm3 C. 0.360 dm3 D. 0.420 dm3 182 Sulphur dioxide is formed by burning sulphur in oxygen. S(s) + O 2 (g) SO 2 (g) Which of the following statements concerning the above reaction is INCORRECT? (Molar volume of any gas at r.t.p. = 24.0 dm3 mol1) A. 1 mole of sulphur reacts with 1 mole of oxygen to give 1 mole of sulphur dioxide at r.t.p.. B. 32.1 g of sulphur react with 1 mole of oxygen to give 24.0 dm3 of sulphur dioxide at r.t.p.. C. 1 mole of sulphur reacts with 24.0 dm3 of oxygen to give 64.1 g of sulphur dioxide at r.t.p.. D. 24.0 dm3 of sulphur reacts with 24.0 dm3 of oxygen to give 24.0 dm3 of sulphur dioxide at r.t.p.. 183 0.2 g of calcium was added to excess dilute hydrochloric acid at .r.t.p.. What is the volume of gas produced? (Molar volume of any gas at r.t.p. is 24.0 dm3 mol1) A. 20 cm3 B. 60 cm3 C. 100 cm3 D. 120 cm3
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HKDSE Chemistry A Modern View Part IX Rate of Reaction
184 When 0.01 mole of metal Y reacts with excess dilute acid, 240 cm3 of hydrogen is given off at room temperature and pressure. Which of the following is the correct equation for the reaction? (Molar volume of any gas at r.t.p. = 24.0 dm3 mol1) A. Y + 2H+ Y2+ + 2H B. Y + 2H+ Y2+ + H 2 C. 2Y + 2H+ 2Y + H 2 D. 2Y + 6H+ 2Y3+ + 3H 2 185 If 7.0 g of nitrogen and 15.0 g of gas Y have the same number of moles. What is the volume of 15.0 g of gas Y at r.t.p.? (Molar volume of any gas at r.t.p. = 24.0 dm3 mol1) 186 Consider the following chemical reaction: Mg(s) + 2HCl(aq) MgCl 2 (aq) + H 2 (g) What is the volume of hydrogen gas produced when 24.3 g of magnesium reacts with excess hydrochloric acid at r.t.p.? A. 12.0 dm3 B. 24.0 dm3 C. 36.0 dm3 D. 48.0 dm3 187 3.25 g of liquid nitrogen is taken out from a freezer and placed at r.t.p. Finally it turns back to nitrogen gas. Both liquid nitrogen and nitrogen gas exist as N 2 . What is the final volume of the nitrogen gas? A. 200 dm3 B. 103 dm3 C. 5.57 dm3 D. 2.78 dm3 188 If the number of moles of a gas at r.t.p. is given, which of the following can be calculated? (1) Mass of the gas 53
HKDSE Chemistry A Modern View Part IX Rate of Reaction
(2) Volume of the gas (3) Number of formula units of the gas A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) 189 What is the volume of carbon dioxide formed at r.t.p. during the complete combustion of 5.5 g of methane? A. 826 cm3 B. 166 cm3 C. 8.26 dm3 D. 16.6 dm3 190 What is the mass of H 2 O formed in the complete combustion of 240 cm3 of ethane at r.t.p.? A. 0.35 g B. 0.54 g C. 0.63 g D. 0.72 g 191 What is the number of atoms in 2.80 g of carbon monoxide at room temperature and pressure? A. 1.20 × 1023 B. 2.01 × 1023 C. 6.02 × 1022 D. 6.02 × 1023 192 When 0.2 g of magnesium carbonate is treated with excess dilute nitric acid, what volume of gas will be produced at room temperature and pressure? A. 0.029 dm3 B. 0.057 dm3 C. 5.7 cm3 D. 48 cm3 54
HKDSE Chemistry A Modern View Part IX Rate of Reaction
193 2Al(s) + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3H 2 (g) What is the volume of hydrogen gas formed at r.t.p. when 5.4 g of aluminium dissolves in excess dilute sulphuric acid? A. 7.2 dm3 B. 4.8 dm3 C. 3.6 dm3 D. 2.4 dm3 194 A student uses hydrochloric acid to react with sodium carbonate at r.t.p. If hydrochloric acid is the limiting reagent, what volume of carbon dioxide can be produced from 50 cm3 of 1.0 M hydrochloric acid? A. 0.60 dm3 B. 1.2 dm3 C. 1.8 dm3 D. 2.4 dm3 195 C 3 H 8 (g) + 5O 2 (g) 3CO 2 (g) + 4H 2 O(l) 2.0 g of C 3 H 8 (g) undergoes complete combustion to give CO 2 (g) and H 2 O(l) at r.t.p. Calculate the volume of O 2 required in this combustion. A. 24.0 dm3 B. 5.47 dm3 C. 12.0 dm3 D. 3.27 dm3 196 What is the volume of gas evolved when dissolving 0.5 g of magnesium ribbon in excess sulphuric acid? A. 494 cm3 B. 674 cm3 C. 4.94 dm3 D. 6.74 dm3 197 0.623 g of ethane occupies a volume of 498 cm3 at r.t.p. Calculate the molar volume 55
HKDSE Chemistry A Modern View Part IX Rate of Reaction
of ethane at r.t.p. A. 24.2 cm3 B. 22.7 cm3 C. 23.9 dm3 D. 24.5 dm3 Each question below consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table:
A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement. B. Both statements are true and the 2nd statement is NOT a correct explanation of the 1st statement. C. The 1st statement is false but the 2nd statement is true. D. Both statements are false.
Section 40.1 198 Under the same temperature and pressure, the molar volume of any gas must be the same.
Molar volumes of different solids and liquids are unequal at the same temperature and pressure.
199 The unit of molar volume is mol dm3.
Molar volume is the volume occupied by one mole of a substance.
200 Solids and liquids DO NOT have molar volume.
Changes in temperature and pressure have significant effect on molar volume of gases.
Section 40.2 201 1 mole of magnesium has equal volume as 1 mole of iron at room conditions.
According to the Avogadro’s Law, equal volumes of any substances contain the same number of particles at the same
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HKDSE Chemistry A Modern View Part IX Rate of Reaction
temperature and pressure. 202 1 mole of oxygen reacts with excess carbon to give 1 mole of carbon dioxide at r.t.p..
100 cm3 of oxygen reacts with excess carbon to give 100 cm3 of carbon dioxide at r.t.p.
203 1 dm3 of H 2 and 1 dm3 of O 2 DO NOT contain the same number of molecules at 100C and 2 atm.
According to the Avogadro’s Law, equal volumes of all gases contain the same number of molecules only at room temperature and pressure.
Section 40.3 204 A gas with greater molar mass occupies a greater volume.
The molar mass of a gas can be determined by measuring the volume of one mole of the gas and its density at r.t.p.
205 The volume occupied by 1 mol of steam is 24.0 dm3.
The molar volume of any gas is about 24.0 dm3 mol1 at r.t.p.
206 The molar volume of water is 0.018
Molar mass of water is 18.0 g mol1.
dm3 mol1 if its density is 1 g cm3.
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