THE PRESIDENTS OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

032/2A CHEMISTRY 2A

 (ACTUAL PRACTICAL) 

(For Both School and Private Candidates)

Time: 2:30 Hours September 2022.

Instructions

1. This paper consists of two (2) questions.
2. Answer BOTH questions.
3. Cellular phones and any unauthorized materials are not allowed in the examination room.
4. Non-programmed calculators are allowed.
5. Write Your Examination Number on every page of your answer booklet(s).
6. The following constants might be needed in your calculations 

Atomic masses: H = 1, C = 12, O = 16, Na = 23, S = 32, Cl = 35.5 1 litre = 1dm³ = 1000cm³ = 1000mls.

1. You are provided with the following:

Solution PP : Made by diluting 100cm³ of 1M to 1000cm³ of Hydrochloric acid solution.

Solution QQ: Made by dissolving 53g of Y₂CO₃ to make a 1 litre solution.

Indicator MO: Methyl orange.

Procedures:

1. Fill the burette with solution PP.

2. Transfer 20 or 25cm³ of solution QQ to a conical flask using a respective pipette.

3. Titrate solution PP against solution QQ using two drops of MO-indicator.

4. Repeat the titration to obtain three more titre values and record your results in tabular form.

Questions:

(a) (i) Complete the table of the results and work out the average volume of the acid

(PP) used.

(ii) ____________cm³ of PP (acid) required _________cm³ QQ (base) for complete neutralization.

(iii) The colour change of indicator is from _______________ to _____________.

(b) Calculate the molarity of the acid.

(c) (i) Write the balanced equation for the reaction between PP and QQ.

(ii) Calculate the molarity of base Y₂CO₃.

(d) Calculate:

(i) The atomic mass of Y in the formula Y₂CO₃.

(ii) Identify the element Y.

(iii) Write the chemical formula of Y₂CO₃.

2. You are provided with unknown sample of simple salt named as X made up of one cation and one anion. Carry out systematic procedures as guided below to identify the cation and anion present in the salt.

EXPERIMENT TABLE:

(a) Conclusion:

(i) The cation in solid sample X is __________ and anion is ___________________

(ii) Name of sample X is _______________________________________________

(iii) The chemical formula of sample X is ___________________________________

(b) With the aid of a balanced ionic equation explain the type of reaction between sample solution X with sodium hydroxide (NaOH).

THE PRESIDENTS OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM FOUR PRE-NATIONAL EXAMINATION

CODE 032/2A CHEMISTRY 2A

TIME: 2HOURS September 21, 2022

INSTRUCTIONS:

1. This paper consists of two (2) questions. Answer all questions.
2. Each question carries twenty-five (25) marks
3. Qualitative analysis guide sheets authorized by NECTA and non-programmable calculators may be used.
4. Cellular phones and any unauthorized material are NOT allowed in the examination room.
5. Write your name on every page of your answer sheets provided.
6. You may use the following constants.

• Atomic masses: H=1, C=12, Na=23, Cl=35.5
• 1 litre =1 dm³=1000 cm³

1. You are provided with the following solutions;

• Solution X: Containing 0.1M of hydrochloric acid.
• Solution Y: Containing 2.65g of G2CO3 per 0.5L of solution.
• Methyl orange indicator

Procedure:

Put the solution X into the burette. Pipette 20 ml or 25ml of solution Y into a titration flask. Add three drops of methyl orange indicator. Titrate this solution X against the solution Y until the end point is reached. Repeat the titration to obtain three more values and record your results as shown in tabular form.

a) i.) Draw the table of results and complete it by filling the titre values.

ii) Calculate the average volume of acid used.

iii) The colour change at the end point was from______ to______ .

b) Calculate the molarity of Solution Y.

c) Determine the atomic mass of G in G2CO3 and name it.

2. You are provided with the following

• Solution A containing 0.5M sodium thiosulphate
• Solution B containing 0.1M sulphuric acid
• A piece of paper marked ‘X’ and stop watch.

PROCEDURE

(i) Using a measuring cylinder measure 10ml of solution A and pour it into the 50ml beaker.

(ii) Measure 10ml of solution B using different measuring cylinder.

(iii) Pour solution B into the beaker containing solution A and start the stop watch immediately.

(iv) Swirl the flask twice and observe the cross ‘x’ on the marked paper until it disappears.

(v) Record the time. Through away the contents of the beaker and rinse it.

(vi) Repeat the procedure using the volume of A and mix with distilled water as shown below;

Table 1

a) Complete the table above.

b) With the aid of state symbols write the balanced chemical equation for the reaction between B and A solutions.

c) Give three differences between the two major allotropes of a substance which clouds letter “x”.

d) Plot the graph of

1. Volume of Na2S2O3(ml) versus time(s).
2. Volume of Na2S2O3(ml) versus rate (s^–1).

e) From the experiment you attempted, what conclusion can you draw?

PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM IV PRACTICAL EXAMINATION

CHEMISTRY 2A (ACTUAL PRACTICAL)

24 HOURS ADVANCED INSTRUCTION

1. IMPORTANT

1.1 Great care must be given not to divulge the instructions to both candidate and unauthorized person either directly or indirectly

1.2 Note that you will not be allowed to open the envelope containing the question paper before commencement of the examination

2.0 Preparation and labeling of chemicals

Question 1

• Prepare 0.1 M of NaOH and label it M
• Prepare 0.1 M of HCl acid and label it K
• Supply MO indicator

Question 2

Supply 3.0g FeSO₄ and label it Y

PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM IV PRACTICAL EXAMINATION

CHEMISTRY 2A

ACTUAL PRACTICAL

TIME:2:30 Hours

Instructions

1. This paper consists of two(2) questions.Answer all the questions

2. Each question carries twenty-five (25) marks

3. Qualitative Analysis Guide sheet authorized by NECTA and non-programmable may be used

4. Cellular phones are not allowed in examination room

5. Write your Examination number on every page of your answer booklet(s)

6. You may use the following constant.

Atomic masses:H=1, C=12, Na=23, Cl=35.5

1 litre =1 dm³=1000 cm³

1. You are provided with;

1.1. Solution K containing 8.94 g/dm³of HQ acid solution per cubic decimeter of solution.

1.2. Solution M containing 2.0g of sodium hydroxide in 0.5.

1.3. Methyl orange indicator.

Procedure:

Put solution K into a burette. Pipette 25cm³ or 20cm³ of solution M into a titration flask. Add two drops of methyl orange indicator. Titrate the solution M against solution K until a colour change is observed. Repeat the procedure to obtain three more readings and record your results in tabular form.

Questions

(a)How much volume of the acid required to neutralize completely 20cm³ or 25cm³ of base?

(b)The colour change during titration was from . . . . .... to . . . . . . . .

(c)Write balanced chemical equation for this reaction

(d) Calculate the molarity of the M and that of K

(e) Find the molar mass of HQ and identify element Q

2. Sample Y is a simple salt containing one cation and one anion. Carry out experiments described in the experimental table. Carefully record your observations and make appropriate inference to identify the cation and anion present in sample Y

Conclusion

(a) (i) The cation in sample Y is . . . . . . . . .. And anion is . . . . . . .

(ii) The name of sample Y is . . . . . . . . . . . . . .

(iii) The chemical formula of sample Y is . . . . . . ...

(b) Explain the effect of Barium chloride solution to the sample Y

THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM FOUR PRACTICAL EXAMINATION SERIES

CHEMISTRY 2A (ACTUAL PRACTICAL)

24 HOURS INSTRUCTIONS

1. IMPORTANT

1. GREAT CARE MUST BE TAKEN NOT TO VAGUE THESE INTRUCTIONS TO BE BOTH CANDIDATE AND UNAUTHORISED PERSONS EITHER DIRECTLY OR INDIRECTLY.
2. NOTE WILL BE ALLOWED TO OPEN THE ENVELOPE CONTAINING QUESTION PAPERS BEFORE THE TIME COMMENCEMENT OF THE EXAMINATION.

2. PREPARATION AND LABELING OF CHEMICALS

2.1 QUESTION 1

Prepare the following

• 0.015 M oxalic acid solution. Label it F and allow 100 cm³ per candidate.
• 0.018 M sodium hydroxide. Label it G and allow 100 cm³per candidate.
• Phenolphthalein indicator and methyl orange indicator to be shared in the ratio of one to two candidates.

2.2 QUESTION 2

• Provide 3g of calcium carbonate per candidate. Label it N.
• Distilled water 100cm³ per candidate.
• Prepare the following bench reagents to be shared;
  • Dilute hydrochloric acid
  • Dilute nitric acid
  • Sodium hydroxide
  • Ammonia solution

3.0 NOTE TO EXAMINATIONS SUPERVISOR AND LABORATORY TECHNICIAN/HEAD OF CHEMISTRY DEPARTMENT

Laboratory Technician or Head of Chemistry Department should perform an experiment of question 1 during the last thirty (30) minutes of the examination time and submit to the marker the experimental results together with the candidates’ data (Answer sheet).

THE PRESIDENT’S OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

FORM IV PRACTICAL EXAMINATION

CHEMISTRY 2A

(ACTUAL PRACTICAL)

TIME: 2:30HRS

INSTRUCTIONS

1. Each question carries 25 marks.
2. Qualitative analysis Guidance sheets authorised by NECTA and no-programmable calculators may be used.
3. Cellular phones and any unauthorised materials are not allowed in the examination room.
4. Write your Examination number on every page of your answer sheet.
5. The following constants may be used where necessary: Atomic masses: H = 1, O = 16, Na= 23, C = 12.
6. You are provided with the following

1. F: A solution made by diluting 50 ml of 1.5M oxalic acid (H₂C₂O₄) to make 5litres of a solution.

G: A solution containing 0.45g of impure sodium hydroxide (NaOH) in 0.5litre of a solution.

MO Methyl orange indicator

POP Phenolphthalein indicator

Procedure

1. Pour solution F in the burette
2. Pipette 20ml or 25ml of solution G and put it in the titrating flask then add two drops of the suitable indicator among the indicators given above.
3. Titrate solution F in the burette against solution G in the flask until the colour change is observed.
4. Record the volume of solution F required to neutralize solution G.
5. Repeat the procedure (i) to (iv) to obtain three more volumes of solution F.
6. Tabulate your results as follows:

1. Complete the table of results.
2. Find the average volume used.
3. (i) ml of solution F required ml of solution G for complete neutralization.

(ii) The colour of the indicator at the end point was .

4. Which indicator did you choose? Why?
5. How many moles of solution F were required for complete reaction?
6. Showing your calculations clearly, calculate the percentage purity of sodium hydroxide.
7. Suggest two sources of error in this experiment.

2. Sample N is a simple salt. Carry out the experiments described below. Record your observations and make appropriate inferences and finally identify the anion and cation present in the sample N.

Conclusion

A) (i) The cation in sample N is .

(ii) The anion in sample N is .

(iii) The chemical formula of sample N is .

B) With state symbols, write the balanced chemical equation for the reaction taking place in (b) and (d).

C) Mention two uses of N