PAPER 1 YEAR 2011

1) (a) What name is given to the process by which alcohol is formed from a carbohydrate?

(1 mark )

(b) Explain why the solubility of ethane in water is lower than that of etlianol. (2 marks)

2) Complete the nuclear equation below:

(b) The half-life of I is 8 days.

Determine the mass of I remaining if 50 grammes decayed for 40 days. (1 mark)

(c) Give one harmful effect of radioisotopes. (1 mark)

3) A mixture contains ammonium chloride, copper (II) oxide and sodium chloride.
Describe how each of the substances can be obtained from the mixture. (3 marks)

4) The set-lip below shows how nitrogen gas is prepared in the laboratory.

(a) Describe how nitrogen gas is formed in the flask. (2 marks)

(b) Nitrogen is inert. State one use of the gas based on this property.

5) The diagram below represents part of the periodic; table. Use it to answer questions that follow:

M Q

T V W

(a) Write the electronic arrangement for the stable ion formed by W.

(b) Write an equation for the reaction between V and Q.

(c) How do the ionization energies of the elements M and T compare?

Explain. (1 mark)

6) A certain mass of gas occupies 0.15dm~ at293K and 98,648.5Pa. Calculate its volume at I01325Pa mid 273K. (2 marks)

7) When lead(II) nitrate is heated, one of the products is a brown gas.

(a) Write the equation of the reaction that occurs. (1 mark)

(b) If 0.290dm3 of the brown gas was produced, calculate the mass of the lead (II) nitrate that was heated. (R.F.M of lead (II) nitrate = 331; Molar gas volume – 24dm3 ). (2 marks)

8) (a) What is meant by a strong acid? (1 mark)

(b)In an experiment. 40cm3of 0.5M hydrochloric acid was reacted with excess sodium $ carbonate and the volume of carbon (IV) oxide produced recorded with lime. In another experiment, the same volume and concentration of ethanoic acid was also reacted with excess sodium carbonate and the volume of carbon(IV) oxide produced recorded with time.

On the grid below, sketch and label the curves if the volumes of carbon (IV) oxide were plotted against time. (2 marks)

Time (min)

9. State two reasons why hydrogen.is not commonly used as a fuel. (2 marks)

10. During a class experiment, chlorine gas was bubbled into a solution of potassium iodide.
(a) State the observations made.

(b) Using an ionic equation, explain why the reaction is redox. (2 marks)

11 Exhaust fumes of some cars contain carbon (II) oxide and other gases

  1. Explain how carbon (II) oxide is formed in the internal combustion engines.

(1 mark)

(b) Name two gases other than carbon (II) oxide that are contained in exhaust fumes and are pollutants. (2 marks)

12 Sodium hydroxide can be prepared by the following methods; I and II.

I. Sodium metal cold water Sodium hydroxide + Hydrogen

II. Concentrated Process A Sodium hydroxide + Chlorine 4- Hydrogen’
Sodium chloride

(a) Name one precaution that needs to be taken in method I. (1 mark)

(b) Give the name of process A. (1 mark)

(c) Give one use of sodium hydroxide. (1 mark)

13 Distinguish between the terms deliquescent and efflorescent as used in chemistry. (2 marks)

14 Two organic compounds P and Q decolorize acidified potassium manganate (VII) solution; but only P reacts with sodium metal to give a colourless gas.
Which homologous series does compound P belong? Give a reason. (2 marks)

15 Soap dissolves in water according to the equation below;

NaSt -——> Na+ + St where St is the stearate ion.

(aq) (aq)

(a) Write the formula of the scum formed when soap is used in hard water. (1 mark)

(b) Write the ionic equation for the reaction that occurs when sodium carbonate is used to remove hardness in water. (1 mark)

16 Ethanoic acid and ethanol react as shown in the equation below:

CH3COOH(l) + C2H5OH(l) CH3 COOC2 H5 (l) + H2O(l)

Other man warming, how would the state of equilibrium be established within a short time?

(1 mark)

17 The set up below was used to prepare a gas and study some of its properties. Study it and answer the questions that follow:

(a) State and explain the observations made in the:

(i) Tube label led A; (1 mark)

(ii) Beaker labelled B. (1 mark)

(b) State one precaution that should be taken when carrying out this experiment.

(1 mark)

18) Under certain conditions, chlorine gas reacts with sodium hydroxide to form sodium hypochlorite.

(a) Name the conditions under which sodium hydroxide reacts with chlorine to form sodium hypochlorite. (1 mark)

(b) State two uses of sodium hypochlorite. (2 marks)

19 50kg of ammonium sulphate (NH4)2SO4 and 30kg of urea CO(NH2)2 fertilizers in two equal sizes of plots A and B to enrich their1 nitrogen content. Show by working, which plot was more enriched with nitrogen. (N = 14; S = 32; O = 16; C = 12; M = J) (3 marks)

20 Describe how the PH of anti-acid (Actal) powder can be determined in the laboratory. (2 marks)

21 Graphite is one of the allotropes of carbon.

(a) Name one other element which exhibits allotropy. (1 mark)

(b) Explain why graphite is used in the making of pencil leads. (2 marks)

22) The table below ‘gives some properties of the fee elements in group (VII) Of the periodic table.

Study it and answer the questions that follow:

Element Atomic

No.

Melting Point

(°C)

Boiling Point

(°C)

Chlorine 17 -101 -34.7′
Bromine . 35. -7 58.8
Iodine 53 114 184

(a) Which element is in liquid form at room temperature? Give a reason. (1 mark)

(b) Explain why the boiling point of iodine is much higher than that of chlorine. (2 marks)

23) The thermal chemical reaction between carbon and sulphur is as shown by the equation below:

C(s) + 2S(s) CS2(s) ∆H = +117.0kJmol-1

 

On the grid below, sketch and label the energy level diagram for the reaction. (2 marks)

Reaction co-ordinate

24) The table below gives the number of electrons, protons and neutrons in substances X, Y and Z

Study it and answer the questions that follow.

Substance Electrons Protons Neutrons
X 10 10

8

10

10

Y 10
z 8 8 8

(a) Which letter represents an ion? (1 mark)

(b) Which of the substances are isotopes? Give a reason. (2 marks)

25) (a) State the Gay Lussac’s Law. (1 mark)

(b) 10cm3 of a gaseous hydrocarbon, C H required 30cm3 of oxygen for complete

combustion. If steam and 20cm of carbon (IV) oxide were produced, what is the value
of X? (2 marks)

26) The data given below was recorded when metal M was completely burnt in air. M is not the

actual symbol of the metal. (R.A.M; M=56, O=16)

Mass of empty crucible and lid = 10.240g

Mass of crucible, lid and metal M = 10.352g

Mass of crucible, lid and metal oxide = 10.400g

(a) Determine the mass of: (1/2 mark)
(i) metal M”; .

(ii) oxygen.

(b) Determine the empirical formula of the metal oxide. (2 marks)

27 The flow chart below shows some:processes involved in ,the industria.lextract.ion of zinc, metal;.

(a) Name one ore from which zinc is extracted. (1 mark)

(b) Write the equation of the reaction taking place in unit .U. (1 mark)

(c) Name two uses of zinc .metal. (1 mark)

28) The diagram below shows the bonding between aluminium chloride and ammonia.

(a) Name the types of bonds that exist in the molecule.

(b) How many electrons are used for bonding in the molecule? (1 mark)

29) Explain why the following substances conduct an electric current.

(a) Magnesium metal. (1 mark)

(b) Molten magnesium chloride. (1 mark)

30) A sample of river water is suspected to contain zinc and sulphate ions.

Describe how the presence of zinc ions and sulphate ions can be established. (3 marks)

31) What name is given to elements which appear in group (II) of the periodic table? (1 mark)

CHEMISTRY

PAPER 2

1. The flow chart below shows some of the processes involved in large scale production of sulphuric (IV) acid. Use it to answer the question that follow.

  1. Describe how oxygen is obtained from air on a large scale (3 marks)
  2. (i) Name substance A. (1 mark)

(ii) Write an equation for the process that takes place in the absorption chamber (1 mark)

(c ) Vanadium (V) oxide is a commonly used catalyst in the contact process.

  1. Name another catalyst which can be used for this process. (1 mark)
  2. Give two reasons why vanadium (V) oxide is the commonly used catalyst
  3. State and explain the observation made when concentrated sulphuric (VI) acid is added to crystals of copper (II) sulphate in a beaker. (2 marks)
  4. The reaction of concentrated sulphuric (VI) acid with sodium Chloride produces hydrogen chloride gas. State the property of concentrated sulphuric (VI) acid illustrated in this reaction.
  5. Name four uses of sulphuric (VI) acid. (2 marks)

2. The set-up below was used by student to investigate the products formed when aqueous copper (II) chloride was electrolyzed using carbon electrodes.

  1. (i) Write the equation for the reaction that takes place at the cathode. (1 mark)
  2. Name and describe a chemical test for the product initially formed at the anode when a highly concentrated solution of copper (II) chloride is electrolyzed. (3 marks)
  3. How would the mass of the anode change if the carbon anode was replaced with copper metal? Explain. (2 marks)
  4. 0.6 g of metal B were deposited when a current of 0.45 A was passed through an electrolyte for 72 minutes. Determine the charge on the ion of metal B.

(Relative atomic mass of B=59, 1 Faraday = 96 500 coulombs) (3 marks)

  1. The electrode potentials for cadmium and Zinc are given below:

Cd2+ (aq) + 2e Cd (s) ; Eѳ = – 0.4v

Zn2+ (aq) + 2e Zn(s) ; Eѳ = – 0.76v

Why is it not advisable to store a solution of cadmium nitrate in a container made of Zinc. (2 marks)

3.(a) Ethanol can be manufactured from ethane and steam as shown in the equation below:

C2H4 (g) + H2O (g) CH3CH2OH (g)

Temperature and pressure will affect the position of equilibrium of the above reaction. Name the other factor that will affect the position of equilibrium of the above reaction.

  1. The data table below was recorded when one mole of ethane was reacted with excess steam. The amount of ethanol in the equilibrium mixture was recorded under different conditions of temperature and pressure. Use the data to answer the questions that follow.
Temperature

(0C)

Pressure

(Atm)

Amount of ethanol at

Equilibrium (Moles)

300 50 0.40
300 60 0.46
300 70 0.55
250 50 0.42
350 50 0.38
  1. State whether the reaction between ethane and steam is exothermine or endothermic. Explain your answer. (3 marks)
  2. State and explain one advantage and one disadvantage of using extremely high pressure in this reaction. (2 marks)

(c ) In an experiment to determine the rate of reaction between calcium carbonate and hydrochloric acid,2g of calcium carbonate were reacted with excess 2 M hydrochloric acid. The volume of carbon (IV) oxide evolved was recorded at regular intervals of one minute for six minutes. The results are shown in the table below.

 

Time (minutes) 1 2 3 4 5 6
Volume of carbon (IV) oxide (cm3) 170 296 405 465 480 480
  1. Plot a graph of time in minutes on the horizontal axis against volume of carbon (IV) oxide on the vertical axis. (3 marks)
  2. Determine the rate of reaction at 4 minutes. (2 marks)

4.(a) When excess calcium metal was added to 50 cm3of 2 M aqueous copper(II) nitrate in a beaker, a brown solid and bubbles of gas were observed.

  1. Write two equation for the reactions which occurred in the beaker. (2 marks)
  2. Explain why it is not advisable to use sodium metal for this reaction. (2 marls)
  3. Calculate the mass of calcium metal which reacted with copper (II) nitrate solution. (relative atomic mass of Ca=40) (2 marks)
  4. The resulting mixture in (a) above was filtered and aqueous sodium hydroxide added to the filtrate dropwise until in excess. What observations were made? (1 mark)
  5. (i) Starting with calcium oxide, describe how a solid sample of calcium carbonate can be prepared. (3 marks)
  6. Name one use of calcium carbonate.

5.(a) Other than their location in the atom, name two other differences between an electron and a proton. (2 marks)

(b) The table below gives the number of electrons, protons and neutrons in particles A, B,C,D,E,F and G

Particular Protons Electrons Neutrons
A 6 6 6
B 10 10 12
C 12 10 12
D 6 6 8
E 13 10 14
F 17 17 18
G 8 10 8

 

  1. Which particle is likely to be a halogen? (1 mark)
  2. What is the mass number of E? (1 mark)
  3. Write the formula of the compound formed when E combines with G.
  4. Name the type of bond formed in (iii) above. ( 1 mark)
  5. How does the radii of C and E compare? Give a reason. (2 marks)
  6. Draw a dot (.) and cross (x) diagram for the compound formed between A and F.
  7. Why would particle B not react with particle D?

6.(a) Study the flow chart below and answer the questions that follow.

  1. I what observation will be made in Step 1? (1 mark)

II Describe a chemical test that can be carried out to show the identity of

Compound C. (2 marks)

  1. Give the names of the following: (2 marks)
  2. Give the formula of substance B. (1 mark)
  3. Name the type of reaction that occurs in: (1 mark)
  4. Give the reagent and conditions necessary for Step (VI). (2 marks)
  5. (b) (i) Name the following structure.

  1. Draw the structure of an isomer of pentene. (1 mark)

7.(a) What is meant by molar heat of combustion?

(b) State the Hess’s Law

  1. Use the following standard enthalpies of combustion of graphite, hydrogen and enthalpy of formation of propane.

  1. Write the equation for the formation of propane.
  2. Draw an energy cycle diagram that links the heat of formation of propane with its heat of combustion and the heats of combustion of graphite and hydrogen. (3 marks)
  3. Calculate the standard heat of combustion of propane. (2 marks)
  4. Other than the enthalpy of combustion, state one factor which should be considered when choosing a fuel.
  5. The molar enthalpies of neutralization for dilute hydrochloric acid and dilute nitric (V) acid are -57.2KJ/mol while that of ethanoic acid is -55.2kJ/mol. Explain this observation. (2 marks)