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CHEMISTRY FORM 3 PPR 1

  1. Give two reasons why non-luminous flame is used in school laboratories.  (2marks)

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  • Name the most suitable method of separation that can be used to separate:

(a) Oil from cashew nut                                                                                                            (1mark)

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b) Sodium chloride from a solution of potassium chloride and sodium chloride mixture 1 mark

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  • Using dots(.) and crosses (x) show the bonding
  • NH4+                                                                                           (1mark)
  • H2O                                                                                            (1mark)
  • The table below gives information on four elements S, T, Q and R. Study it and answer the question that follows.The letters do not represent the actual symbols of the elements
Elements Electronic configuration Atomic radius (nm) Ionic radius (nm)
S Q R T 2.8.2 2.8.7 2.8.8.1 2.8.8.2 0.136 0.099 0.203 0.174 0.065 0.181 0.133 0.099
  • Select two element with similar physical and chemical properties (2marks)

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  • Which one is likely to be a gas at room temperature and pressure? (1mark)

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  • Describe how you can prepare crystals of copper (II)sulphate  starting with copper metal, without using concentrated sulphuric acid    (3marks)

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  •   (b)Give a reason as to why it is not advisable to heat strongly ammonium nitrate.                           (1mark)

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  • When Na2Co3.XH2O is heated strongly it losses 63.20% of mass. Calculate the value of X.

            (Na=23.0, C=12.0,O=16.0,H=1.0)                                                                                         (3mks)

  • (a)Name two allotropes of carbon.     (1mark)

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  1. Explain why diamond is very hard. While graphite is very soft.     (2marks)

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  • (A)Carbon (II) oxide is a‘silent killer’. Explain. (2marks)

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     (B) Chlorine gas was passed through water and two acids were formed. Identify the acids.     (2marks)

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  1.  (a) A mixture of 100cm3 of methane (CH4 ) and 100cm3of oxygen was ignited. Write a chemical equation of reaction.    (1mark)  .………………………………………………………………………………………………………                                                                                                         

(b)Calculate the volume of methane (CH4) which remained unreacted   (2marks)

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  1. Study the flow chart below and answer the question that follows.
  • Name the chemical process in step (1mark)

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            II………………………………………………………………………………     (1mark)

            (b)Give one use of the chemical obtained in step III.      (1mark)

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  1. Calculate the volume of 2MHCl which is required to completly react with 1g of CaCO3 (Ca=40, C= 12, O=16)      (3marks)                                                                                                                            

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  1. The set-up below was used to investigate the effect of steam on copper turnings

            (a)        What was observed in the boiling tube? Explain                                                        (2mks)

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            (b)        Suggest one other metal that would behave as copper turnings in the above set up if used.                                                                                                                                                             (1mk)

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  1. 5.04g of a mixture of anhydrous sodium carbonate and sodium hydrogen when heated to a

constant mass gave 4.11g of residue.

(a)        Write an equation for the reaction that takes place when the mixture is heated        (1mk)

(b)        Calculate the percentage of anhydrous sodium carbonate in the mixture                  (2mks)

  1. The products formed by action of heat on nitrates of element A, B and C are shown below
Nitrate Products formed
A Metal oxide +Nitrogen (IV) Oxide + Oxygen
B Metal +Oxygen (IV) Oxide
C Metal nitrate + oxygen

            (a)        Arrange the metals in order of reactivity                                                                    (1mk)

            (b)        Which element forms a soluble carbonate                                                                  (1mk)

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            (c)        Give an example of B                                                                                                 (1mk)

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  1. Complete the table below    2 mks
Species Atomic mass Number of neutrons Number of electrons Number of protons
V3+ 27     13
Q2-   8   8
  1. Study the information in the table below and answer the questions that follow.The letters are not actual symbols of the element.
Substance                Solubility in water Electrical conductivity
  solid molten
K L M Insoluble Soluble insoluble Good Poor poor Good Good poor

            (a)        Which of the substance is likely to be sodium chloride                                              (1mk)

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            (b)        What type of bond exists in substance K.                                                                  (1mk)

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  1. The diagram below represents a set-up that was used to obtain dry nitrogen from air. Study

                                it and answer the questions that follow.

  • Name solid Q                                                                                                                                     (1mk)

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  • What is the purpose of NaOH(aq) ?                                                                                            (1mk)

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  • Write an equation for the reaction which took place in tube P                     (1mk)
  • Give the name of one impurity in the nitrogen gas obtained.  (1mk)
  • State the observations made in tube p                  (2 mks)

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  1. Complete the table below   4 mks
Indicator                             Colour in
H+(aq) OH(aq)
phenolphthalein    
Melthy orange    
  • Dry ammonia gas was passed over heated copper (II) oxide as shown below

            (a)        State one observation made in tube M.                                                                      (1mk)

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            (b)        Name a suitable drying agent for ammonia gas                                                          (1mk)

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            (c)        Identify gas Y                                                                                                             (1mk)

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21. In the last stage of the Solvay process, a mixture of sodium hydrogen carbonate and ammonia chloride is formed.                                                                                                                      

(i)         State the method of separation used.                                                                         (1mk)

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(ii)        Write an equation showing how lime is slaked  1 mk

  • Name the by-products recycled in the above process 1 mk
  • State and explain the observation that would be made when zinc powder is heated with copper (II) oxide                                                                                                                                       (2mks)

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                        (a)        State Graham’s law of diffusion                                                                    (1mk)

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            (b)        A certain  volume of gas S takes 180 seconds to diffuse through a porous plug.molar mass

of S is 18g.Equal volume of gas Q takes 240 seconds to diffuse through the same plug.

                        Calculate the molar mass of Q.                                                                                   (2mks)

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  •   A student set-up the apparatus shown below attempting to collect oxygen gas.

            (a)        State one mistake the student made                                                                           (1mk)

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(b)        Identify liquid Q                                                                                                         (1mk)

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            (c)        What property enables the gas to be collected as shown above                                 (1mk)

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  •   Study the set-up  below and answer the questions that follows

(a)        State and explain the observation made when the circuit is completed. 2mks                      

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            (b)        What precautions should be taken when performing this experiment? Give a reason(1mk)

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  •   Calcium nitrate is a nitrogenous fertilizer. Calculate the percentage of nitrogen in the fertilizer

            (N=14.0,Ca=40.0,O=16.0)                 (2mks)

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.    (a) State Charles Law.  (1 mark)

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(b) A gas A was found to occupy 300cm3. When the temperature is 470c. Calculate the volume which can be occupied by the gas if the temperature is increased by 200C.  (2marks)

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  •  The apparatus below was set up to show the catalytic oxidation of ammonia
  • Write an equation for the reaction that takes place in the gas jar.  (1mark)

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  • Why is it necessary to have hot nichrome wire in the gasjar.  (1mark)

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  • State one use of ammonia.    (1mark)

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  • The diagram below represents a paper chromatogram for three brands of juices suspected to contain   banned            food colourings
 K                              L                            M  

The results showed the presence of banned food colourings in L and M only. On the same diagram

  • Circle the spots which show banned foodcolouring (1mark)
  • Indicate the solvent front  (1mark)
  • Give one application of chromatography.                                                                 (1mark)

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Name:…………………………………………………..……………Index no ……..…………………………………..

School…………………………………………………………….…. Candidate’s sign ….……………………..

Date: ……………………………………

233/1

CHEMISTRY

PAPER 1

JULY/AUGUST-2015

TIME: 2 HOURS

FORM 3

BOMET COUNTY JOINT   EXAMINATIONS - 2015

Kenya Certificate of Secondary Education (K.C.S.E.)

233/1

CHEMISTRY

PAPER 1

JULY/AUGUST-2015

TIME: 2 HOURS

INSTRUCTIONS TO CANDIDATES:

  • Write your name and index number in the spaces provided above.
  • Answer Allthe questions in the spaces provided below each question.
  • All working MUST be clearly shown where necessary.
  • Sign and write the date of examination in the spaces provided above.
  • Electronic calculators may be used
  • This paper consists of 11 printed pages.
  •  Candidates should check to ascertain that all pages are printed as indicated and that no questions are missing

                                                            For Examiner’s Use Only

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