0515 CHEMISTRY 2018 P2
O/LEVEL CHEMISTRY - JUNE 2018 Paper 2
This paper is arranged in three, A, B and C.
Section A: Answer 4 questions out of 5;
Section B: Answer 2 question out of 3 and
Section C: Answer both questions
USEFUL DATA:
Relative Atomic Masses
Hydrogen (H) = 1.0
Carbon (C) = 12.0
Oxygen (O) = 16.0
Copper (Cu) = 64.0
1 Faraday = 96000 coulombs.
Molar volume of a gas at r.t.p. = 24000cm3
Specific heat Capacity of water = 4.2J/g°C
Avogadro Number = 6.02 xl023
0°C = 273K
SECTION A: Answer ALL questions in this section
1. Atoms in substances are held together by chemical bonds,
(a) Define a chemical bond (1 mark)
(b) Identify the bond type in each of the following. substance
(i) Magnesium chloride
(ii) Ammonia
(iii) Copper (Cu) (3 marks)
(c) Show using diagrams how bonding occurs in magnesium chloride (3 marks)
(d) Give two properties of Ammonia and relate each property to the bond type (2 marks)
(e) Which particles in copper are responsible for conducting electricity? (1 mark)
(TOTAL = 10 MARKS)
2. This question concerns Group I and II elements,
(a) Give the general or family name of group I and II elements
Group I...........(1 mark)
Group II..........(1 mark)
(b) List two physical differences between the two groups of elements (2 marks)
(c) (i) Give one similarity and one difference between sodium (Na) and magnesium (Mg) in their behaviour towards water.
Similarity:........(1 mark)
Difference.......(1 mark)
(ii) Write a balanced equation for the reaction which occurs when sodium is added to water (1 mark)
(d) What type of oxides do elements of group I and II form? (1 mark)
(e) Lithium (Li) in Group l period 2 resembles magnesium (Mg) in group II, period 3. Show how Li resembles Mg using two chemical equations. (2 marks)
(TOTAL = 10 MARKS)
3. This question concerns the following flow diagram
(a) Which one of the compound shown above is a salt? (1 mark)
(b) Suggest a reagent which could be used to convert
(i) Ethanol to ethene (1 mark)
(ii) Ethanol to Ethylethanoate (1 mark)
(c) (i) Give the reaction conditions necessary to convert ethene to ethane. (2 marks)
(ii) Write an equation for the reaction (2 marks)
(d) What is the other product obtained when sodium hydroxide is reacted with ethylethanoate? (1 mark)
(e) What type of reaction occurs in each of the following changes
(i) Ethanol to ethanoic acid (1 mark)
(ii) Ethene to Ethane (1 mark)
(f) Ethene is a monomer. Give the polymer formed from etheane, stating the reaction conditions for the polymerisation process.
Polymer...........(1 mark)
Condition.........(1 mark)
(TOTAL = 10 MARKS)
4. The equation A and B below represent two reactions with the energy changes indicated
A: CO(g) + 2H2(g) ---> CH3OH(g), ▲H = +9lKmol-1
B: 2CH3OH (i) + 302(g) ---> 2CO2(g) + 4H2O(g), ▲H = 384Kmo1-1
(a) Define combustion (1 mark)
(b) (i) What does the symbol ▲H above represent? (1 mark)
(ii) From AH values, state the type of reaction taking place in each case
- Type of reaction A.........(1 mark)
- Type of reaction B..........(1 mark)
(c) Represent reaction A on a well-labelled energy diagram. (2 marks)
(d) (i) Calculate the heat change if 16g of methanol were completely burnt. (2 marks)
(ii) The complete combustion of 8g methanol raised the temperature of 500g of water by 40°C. Assuming that no heat was lost determine the heat of combustion of methanol (2 marks)
(TOTAL = 10 MARKS)
5. This question concerns the industrial production of ammonia and nitric acid
(a) State the raw materials used in the production of
(i) Ammonia (1 mark)
(ii) Nitric acid (1 mark)
(b) Write equations starting from the raw materials to illustrate the production of nitric acid. (3 marks)
(c) State the catalyst needed in the production of nitric acid (1 mark)
(d) Pure nitric acid is colourless but often it has a yellowish brown colour Explain (1 mark)
(e) Ammonia and nitric acid are used for the production of fertilizers. State a fertilizer produced from
(i) Ammonia (1 mark)
(ii) Nitric acid (1 mark)
(f) Why is an all. glass apparatus used in the laboratory preparation of nitric acid? (1 mark)
(TOTAL = 10 MARKS)
SECTION B
Answer any two questions. All questions carry equal marks. Where appropriate, equations and diagrams should be used to illustrate your answer.
6. Temperature, concentration, surface area and light are factors that affect the rate of chemical reactions. Using a
suitable example in each case, discuss how each of these factors affects the reaction rate.
(20 marks)
7. Electrolysis is used in the industry to manufacture compounds and to purify elements. Choose one compound
and one element and show the application of electrolysis in each case
(20 marks)
8. Write short notes on each of the following;
(a) Polymerisation
(b) Cracking
(c) Isomerism
(d) Saturated and unsaturated hydrocarbons
(20 marks)
SECTION C
ANSWER ALL QUESTIONS IN THIS SECTION
9. (a) You are provided with the following laboratory apparatus and reagents: dilute hydrochloric acid 0.05M sodium hydroxide, pipette, burette and phenolphthalein. You are required to design an experiment to determine the concentration of dilute hydrochloric acid.
(i) Sketch the set-up used to determine the concentration of dilute hydrochloric acid indicate clearly the contents of each container (4 marks)
(ii) Which apparatus is used to transfer 25cm3 of dilute hydrochloric acid into the conical flask? (1 mark)
(iii) State the use of phenolphthalein (1 mark)
(iv) What colour change will occur in the beaker containing phenolphthalein?
- Initial colour........(1 mark)
- Colour at end point...(1 mark)
(v) The following table shows the results obtained by the students
From the table above calculate the titre of the acid (1 mark)
(vi) If 20cm3 of dilute hydrochloric acid was used for the titration, write the equation of the reaction taking place and calculate the concentration of dilute hydrochloric acid. (3 marks)
(vii) What type of reaction is this? (1 mark)
(b) You are given two gases: hydrogen chloride (HCl(g)) and carbon dioxide (CO2(g)). Draw an experimental set up that could be used to dissolve each of these gases in water.
- (HCL(g))...... (2 marks)
- CO2(g)..........(2 marks)
(c) You are provided with the following mixtures: sulphur/Iron fillings, Kerosene/water and green pigment of a leaf. State the separating method you would use to separate each mixture.
(3 marks)
(TOTAL = 20 MARKS)
10. (a) Below is a table of some procedures and observations carried out to analyse compounds A,B,C and D. Read the procedures and observations carefully and draw the necessary and logical conclusion as requested in the questions that follow.
(b) While carrying out a flame test on a compound W, a bluish flame is observed and on heating W , the compound decomposes producing a brown gas X and another gas Y, that rekindles a glowing splint.
(i) Which cation in compound W is responsible for the blue flame? (1 mark)
(ii) Identify gases X and Y
- Gas X...........(0.5 mark)
- Gas Y............(0.5 mark)
(iii) Identify compound W
- Compound W.........(1 mark)
(iv) Write an equation for the decomposition of W. (1 mark)
(c) Into 3 different test-tubes, A, B and C, containing 2cm3 of unknown solutions K,L and M. 2cm3 of acidified BaCl2 solution was added into each of the 3 test-tubes.
(i) In test-tube A, a white precipitate is immediately formed. Identify the likely ion present in solution (1 mark)
(ii) In test-tube B an effervescence occurs, producing a colourless gas that decolorises acidified KMno4. Identify the gas evolved and the ion present in solution. Describe a simple laboratory test for this gas.
- Gas evolved...........(2.5 marks)
- Ion present.............(2.5 marks)
(iii) In test-tube C, effervescence occurs producing a gas commonly used in fire extinguishers. Describe a simple laboratory test for this gas. (3 marks)
(TOTAL = 20 MARKS)
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