THE UNITED REPUBLIC OF TANZANIA

PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

MADABA DISTRICT COUNCIL

MADABA DISTRICT MOCK EXAMINATION-2021

032/2A CHEMISTRY 2 (ACTUAL PRACTICAL) FORM FOUR

TIME 2:30 HOURS 25/06/2021AM

INSTRUCTIONS

  1. This paper consists of TWO questions
  2. Answer ALL questions in this paper
  3. In question ONE , an account of the procedure is not required
  4. In question TWO ,credit will be given for precisely recorded observations and for correctly presented inferefences
  5. All answers must be written in black or blue ink EXCEPT for drawings which must be in pencils
  6. You may be allowed to use qualitative analysis quidance shets after the superisor has CERTIFIED that such guidance sheetd have NOT been tempered with
  7. Remember to write your Examination number on every page of your answer sheet provided .
  8. The following constatnts may be used in your calculations

    Atomic masses : H-1,0=16, S=32, C=12, N=14, Na =23

    1dm3=1litre =1000cm3

     

    1. You are provided with the following solutions,

      Solution AA=contains 3g of acetic acid dissolved in 500cm3 of the solution

      Solution BB: Contains sodium hydroxide of unknown concentration

      M.O. Methyl orange

      P.O.P: Phenolphthalein

      Procedures

      Pipettle 20 or 25cm3 of solution BB into a conical flask . Add 2-3 drops of suitable indicators of your choice . Titrate this solution with solution AA from the burette until the colour of your change is observed. Repeat this procedure to obtain three other consistent resalts .

      Record our results in a tabular form

      Questions

      1. State the volume of pipette used
      2. Calculate the average volue of solution AA used
      3. Mention the type of Indicator used in this experiment . Give reason for your answer.
      4. What was the colour change of the indicator you have chosen at the end –point of the titration
      5. What is the significance of the colour change when enough AA has been added to solution BB?
      6. Write a balance chemical question eation for the reaction between AA and BB
      7. Calculate the concentration of BB
        1. Moles per litre
        2. Grams per litre
    2. You are provided with a salt EE which has a singule CATION nad ANION perfom the tests below to establish the identify of the salt

TEST

OBSERVATION

INFERENCE

  1. Appearance of sample EE
   
  1. Place a spatula of sample EE in a test tube and heat while rotating the test tube . Test for any gas (es) evolved
   
  1. (i)Place a spatula of sample EE in test tube and add dilute hydrochrolic acid

(ii)Heat the contents of the above test tube and allow to cool to room temperature

(iii)To the above add concentrate hydrochloric acid

   

4(a)Place a spatula of sample EE in attest tube and add dilute nitric acid . Test for the gas (es) evolved

   

(b)Divide the resulted solution in two portions

(i) To one portion add potassium chromate solution

(ii) To the second portion add potassium iodide solution

(iii)Warm the contents of the above (second) test tube and then allow to cool

   

 

Conclusion

In sample EE, the cation is …………….. and anion is ……………. Usng reaction equations, show that what happened in experiments 2 and 4 (a) above

Write the banced chemical equations for the reactions in

  1. Experiment 2
  2. Experiment 4(a)

Leave a Reply

Your email address will not be published.