THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA FORM TWO NATIONAL ASSESSMENT

032 CHEMISTRY

Time: 2:30 Hours Year: 2023

Instructions

1. This paper consists of sections A, B and C with a total of ten (10) questions.
2. Answer all the questions.
3. Section A and C carry fifteen (15) marks each and section B carries seventy (70) marks.
4. All writing must be in black or blue ink except diagrams which must be in pencil.
5. Cellular phones and any unauthorized materials are not allowed in the assessment room.
6. Write your Assessment Number at the top right corner of every page.
7. The following atomic masses may be used: H = l , C = 12, O = 16, Cl = 35.5.

SECTION A (15 Marks)

Answer all questions in this section.

For each of the items (i) - (x), choose the correct answer from the given alternatives and write its letter in the box provided.

(i) What are the common activities done in the chemistry laboratory?

1. Exhibitions 
2. Demonstrations 
3. Exercises 
4. Experiments

(ii) The following substances are constituents of a First Aid Kit in the chemistry laboratory, except:

1. petroleum jelly 
2. iodine tincture
3. cotton wool 
4. plaster of paris

(iii) What is the suitable method for separating a mixture of sand and ammonium chloride?

1. Magnetization 
2. Decantation
3. Sublimation 
4. Simple distillation

(iv) Which one is an example of liquid solutions?

1. Dental amalgam 
2. Fresh milk
3. Alloys 
4. Vinegar

(v) Why do the ships often have blocks of magnesium attached to their hull?

1. To improve appearance of the hull. 
2. To make the hull stronger.
3. To give sacrificial protection to the hull. 
4. To weigh down the ship in the water.

(vi) Given a task of preparing hydrogen gas in the laboratory, which complete set of apparatuses will you use?

1. Thistle funnel, flat-bottomed flask, pipette, water trough, beehive stand and a gas jar.
2. Thistle funnel, flat-bottomed flask, delivery tube, water trough, beehive stand and burette.
3. Thistle funnel, flat-bottomed flask, delivery tube, water trough, beehive stand and a gas jar.
4. Thistle funnel, flat-bottomed flask, delivery tube, measuring cylinder, beehive stand and a gas jar.

(vii) What is the role of charcoal in filter elements?

1. To kill germs 
2. To sediment impurities
3. To coagulate impurities 
4. To trap dust particles

(viii) Why is wind considered a promising source of energy for the future?

1. It does not produce harmful gases.
2. It is easily stored.
3. It is harnessed without chemical reaction. 
4. It is a renewable source of energy.

(ix) Given that, the amount of heat gained by water after a complete combustion of 46 g of ethanol (C2H50H) is 8.4 kJ, what is the energy value of ethanol in J/ ?

1. 182.0 
2. 182.7 
3. 182.6 
4. 182.8

(x) The following sets of radicals have oxidation states of either -l or -2 except; 

1. hydroxide, carbonate, nitrate, phosphate, chlorate and sulphite.
2. hydroxide, sulphate, carbonate, nitrate, nitrite, chlorate and sulphite.
3. hydroxide, carbonate, nitrate, chlorate and hydrogen carbonate. 
4. hydroxide, carbonate, nitrite, chlorate, sulphate and nitrate.