THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA CERTIFICATE OF SECONDARY EDUCATION EXAMINATION

032/1 CHEMISTRY 1

(For Both School and Private Candidates)

Time: 3 Hours Year: 2024

Instructions

1. This paper consists of sections A, B and C with a total of eleven (11) questions.
2. Answer all questions in sections A and B and two (2) questions from section C.
3. Sections A carries sixteen (16) marks, section B fifty four (54) marks and section C thirty
   (30) marks.
4. Non-programmable calculators may be used.
5. Communication devices and any unauthorised materials are not allowed in the examination room.
6. Write your Examination Number on every page of your answer booklet(s).
7. The following constants may be used.

• Atomic Masses: H = 1, N = 14, 0 = 16, Cl = 35.5, Ca = 40

SECTION A (16 Marks) 

Answer all questions in this section.

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

(i) Which ideas were introduced by Dalton?

(i) Atoms cannot be created or destroyed.

(ii) Atoms of the same element may have different chemical properties.

(iii) Atoms of different elements may have the same chemical properties.

(iv) When atoms combine they do so in simple whole numbers to form compounds. 

1. (ii) and (iv) 
2. (i) and (iii) 
3. (ii) and (iii)
4. (i) and (iv) 
5. (i) and (ii)

(ii) A Form Four student boiled a mixture of sun-flower oil and concentrated solution of sodium hydroxide for a certain period of time. After cooling, sodium chloride salt was added to the mixture. What was the aim of this experiment?

1. To prepare an alcohol
2. To prepare a solid soap
3. To prepare sodium metal
4. To prepare a carboxylic acid
5. To prepare an organic compound

(iii) In Periodic Table, hypothetical elements X and Y are found in group VI and II respectively. What is the correct formula for the compound formed between the two elements?

1. XY 
2. YX 
3. X₆Y₂
4. Y₂X₆ 
5. X₃Y

(iv) How is Mendeleev's Periodic Table differs from the modern Periodic Table?

1. Mendeleev's Periodic table does not include noble gases while Modern
   Periodic table includes them.
2. Mendeleev's Periodic table does not include non-metals while Modern Periodic table includes them.
3. Mendeleev's Periodic table does not include halogens while Modern Periodic table includes them.
4. Mendeleev's Periodic table has only 7 groups while Modern Periodic table has 8 groups.
5. Mendeleev's Periodic table organise elements by increasing atomic number while the Modern Periodic table organise elements by atomic mass.

(v) To investigate the solubility of sodium chloride, a technician dissolved different amount of sodium chloride in a specific volume of water while altering the temperature of water. What does temperature represents in this experiment?

1. dependent variable 
2. intermediate variable
3. independent variable 
4. controlled variable
5. fixed variable

(vi) Which property is used to confirm the presence of pure water?

1. It turns white anhydrous copper (II) sulphate blue
2. It dissolves all other substances
3. It freezes at 0 °C
4. It is neutral to litmus paper
5. It turns blue cobalt (H) chloride paper pink

(vii) In which type of oxides does Aluminum oxide belong?

1. Metal oxides 
2. Insoluble oxides
3. Soluble oxides 
4. Amphoteric oxides
5. Basic oxides

(viii) What is the amount of charge when a current of 2 amperes flows through a certain point in an electrolyte for 0.5 second?

1. 2 coulombs 
2. 1 coulombs
3. 2.5 coulombs 
4. 1.5 coulombs
5. 10 coulombs

(ix) How can you prevent a hoe from getting rust?

1. By painting and oiling them.
2. By exposing them to air.
3. By keeping them in moisture.
4. By cleaning them with water after use.
5. By leaving them in the garden after use.

(x) When 2.45 g of zinc granules are dropped in 50 cm³ of acid 'Y', zinc sulphate is formed along with evolution of gas 'NI' which burns with pop sound when kept close to a burning candle. Which one of the following pairs represent the acid Yr and gas M?

1. Sulphuric acid and Carbon dioxide gas.
2. Sulphuric acid and Hydrogen gas.
3. Hydrochloric acid and Oxygen gas.
4. Hydrochloric acid and Hydrogen gas.
5. Sulphuric acid and Oxygen gas.