DEMO~PAPERS 137-QNS

 

PRESIDENT’S OFFICE

REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

MPWAPWA DISTRICT COUNCIL

FORM FOUR PRE-NECTA I EXAMINATION-032/1 CHEMISTRY 1

TIME: 3.00 Hours SEPTEMBER, 2023

INSTRUCTIONS

1. This paper consists of sections A, B and C with the total of Eleven (11) questions.

2. Answer all questions in section A, B and two questions from section C.

3. Cellular phones and any unauthorized materials are not allowed in the examination room.

4. Write your examination number on every page of your answer booklet(s) 5. The following constants may be used;

• Atomic masses= H = 1, O=16, S=32, Cl=35.5, Na=23, C=12, Ag=108.

• Avogadro’s constant:6.02x10²³

• GMV at s.t.p =22.4dm³

• 1 faraday=96,500C

• 1litre=1dm³ =1000cm³

SECTION A (16 marks)

Answer all questions

1. For each of the items i-x, choose the correct answer from among the given alternatives and write its letter in the answer sheet provided.

i. Loose or floppy clothing is not allowed in the laboratory. Why?

1. Movement has to be fast

2. It will get wet when water splashes

3. It may catch fire or cause one to fall

4. It causes poor ventilation in the body

5. It prevents experiment from being conducted well

2. What mass of sulphuric acid (H₂SO₄) is found in 400 cm³ of its 0.1M aqueous solution?

1. 2.67g

2. 9.8g

3. 4.89g

4. 3.92g

5. 8.69g

2. One of the isotopes of an element X has atomic number Z and a mass number A. What is the number of neutrons contained in the nucleus of the element?

A. Z - A

2. A

3. A + Z

4. Z

5. A – Z

2. What is the proper set of apparatus would you use to measure various substances in the laboratory?

1. Stopwatch, beaker, burette and pipette

2. Beaker, pipette, stopwatch and electrical balance

3. Electrical balance, pipette, stopwatch and thermometer

4. Thistle funnel, pipette, burette and measuring cylinder

5. Beaker, measuring cylinder, thermometer and pipette

2. When methane undergoes substitution reaction with excess chlorine, what is the final product?

1. Chloromethane

2. Dichloromethane

3. Trichloromethane

4. Tetrachloromethane

5. Chloroethane

2. Aluminum does not react with water and does not corrode much in air.Why?

1. It is below hydrogen in reactivity series

2. It forms a stable carbonate which prevent reactions

3. The metal is covered with protective coating of an oxide

4. It is very stable

5. Does not react with water

2. Which of the following compounds does not belong to the alkene homologous series?

1. C₂H₄

2. C₃H₆

3. C₄H₈

4. C8H16

5. C5H12

2. Substance X liberates chlorine gas from acidified potassium chloride. What is the behavior described by X

1. Catalysis

2. An oxidation

3. Reduction

4. Decolourization

5. Colorization

2. When a burning fuel produces blue colour it means there is A. Adequate supply of oxygen with production of soot.

2. Inadequate supply of oxygen without production of soot.

3. Inadequate supply of oxygen with production of soot.

4. Adequate supply of oxygen with production of more heat

5. Inadequate supply of oxygen with production of more heat

2. What is the number of molecules in 16.8dm³ of chlorine at S.T.P?

1. 4.52X10²³

2. 6.02X10²³

3. 7.5X10²³

4. 3.14X10²³

5. 9.03X10²³

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