🌊PAPER 27-Qns

 

MARKAZ ISLAMIC SEMINARY

FORM THREE MD-TERM TEST

CHEMISTRY-032

April, 2024-Time: 3:00 Hours

INSTRUCTIONS

1. This paper consists of section A, B and C with a total of 11 questions

2. Answer all questions in this paper

3. Calculators, cellular phones and any unauthorized Materials are not allowed in the examination room

4. Write your examination number on every page of your answer booklets

5. The following constant may be used.

Atomic masses H=1, C= 12. O=16,N= 14, Pb- 108

Avogadro's number 6.02 x 10²³

GMV at S. T.P =22.4 dm³

Faraday= 96500c

standard pressure =760mmHg

Standard temperature =2.73k

I litre=ldm=1000cm³

SECTION A (16 Marks)

Answer all question in this section

1. For each of the items (i) – (x), Choose the correct answer from among the given alternatives then write the correct answer beside the item number in the answer booklet provided

1. Form Four students in a certain school were doing a scientific investigation about malaria disease in the coast region. which among the following scientific procedures was used to accept or reject the hypothesis made .

   1. Data interpretation

   2. Experimentation

   3. Conclusion

   4. Hypothesis formulation

   5. Problem identification

2. The apparatus used to heat small amounts of solid substance within a gas jar is

   1. Evaporation dish

   2. Test tube holder

   3. Deflagrating spoon

   4. Gas jar

   5. Desiccator

3. During sunny days, the water in pounds dry completely leaves the pond barely. Which process takes place in that season?

   1. Condensation

   2. Melting

   3. Evaporation

   4. Sublimation

   5. Deposition

4. If you want the Bunsen burner to have the same flame colour as the candle flame you must

   1. Have an air hole completely opened

   2. Turn on a larger supply of gas

   3. Have air hole completely closed

   4. Have more candle burning

   5. Have completely removed the barrel

5. “Water is referred to as the universe of solvent”. What does this statement mean?

   1. It is commonly known liquid

   2. It exists in all three state of matter

   3. It dissolves more substance than any other known liquid

   4. It is used in cooking, drinking and washing bodies and clothes

   5. It is colourless, odourless and tasteless liquid

6. The simplest formula of a compound formed when combining 36g of magnesium and 14g of nitrogen is

   1. Mg N

   2. mg₂N

   3. Mg₃N₂

   4. mg₂N

   5. Mg₄N₂

7. An element X is found in period 4 and group II of the periodic table. If element X undergoes the reaction.

X X²⁺ + 2e . The electronic configuration of X²⁺ Ions is

(A) 2 : 8 : 6

(B) 2 : 8 : 2

(C) 2 : 8 : 8

(D) 2 : 8 : 4

(E) 2 : 8 : 8 : 2

8. Hard water which can be soften by boiling method contains dissolved

(A) Calcium Carbonate

(B) Calcium Sulphate

(C) Magnesium Chloride

(D) Magnesium hydrogen Carbonate

(E) Sodium Chloride

9. One of the following statement best explains the meaning of an acid

1. It is any substance that contains hydrogen in its formula

2. It is any substance that dissolve in water to produce hydrogen Ions

3. It is any substance that can react with NaOH

4. It is any substance that release hydroxyl Ion when dissolved in water

10. Workers from a cement industry carelessly dispose of waste contaminants with lime to nearby fields. The soil in the field is likely to be

(A) Acidic

(B) Alkaline

(C) Neutral

(D) Amphoteric

(E) As hard as cement

2. Match the items from list A with the correct responses in List B by writing the letter of the correct response in your answer sheets

LIST A	LIST B
The radical with valence of three The element with both metallic and non-metallic properties The most reactive element in the electrochemical series It is formed by contribution of electrons The elements which are incredibly stable and rarely reactive Element with atomic number of 8	Electrovalent compound Potassium Bromine Covalent compound Phosphate Noble gases Oxygen Metalloids

SECTION B (54 Marks)

Answer all question in this section

3.

(a) Before water is used in the public water supply, it has to be treated.

Briefly explain any three ways in which domestic water can be treated

(3 Marks)

(b) A certain hydrocarbon made up of carbon and hydrogen contains 20% by mass of hydrogen and has a vapour density of 15. What is the empirical formula of the compound (6 Marks)

4.

(a) Gas X is colourless, testless and odourless. It is prepared by the reaction between hydrogen peroxide and manganese (IV) Oxide

1. (i) Identify gas X ( 1 Marks)

(ii) State the chemical test for gas X (1 Marks)

2. (i) Write the chemical equation for the production of gas X( 2Marks)

2. Give four uses of gas X (3.5 Marks)

3. Describe the method used to collect the gas (1.5 Marks)

5.

(a) Identify the type of reaction in each of the following chemical equations. Explain your answer

1. CaCo_(s)→CaO_(s) + CO2_(g)

2. Cao_(s) + H₂O_(L)→ Ca(OH)_2(aq)

3. Zn_(s) + CUSO_4(aq) →ZnSO4_(aq) + NaNO_3(aq)

(b) Differentiate between the following terms:

1. Ionic equation and Molecular equation

2. Total Ionic equation and Net Ionic equation

6.

1. How does an oxidation reaction differ from a reduction reaction?

2. The black Compound reacts with hydrogen gas to form brown copper and water as shown below

CUO(s) + H2 (g)→CU(s) + H2O (L)

1. Suggest the types of reaction

2. Which species is a reducing agent? Give reasons ( iii)Which species undergoes oxidation? Give reasons

7.

(a) Element X, Y, Z have atomic number 17, 18 and 20 respectively

1. Write the electronic configuration of each element

2. Based on the reaction, which of the above elements is likely to be found in an uncombined state?

(b) (i) Write down three(3) Characteristics of the bond formed between X and Z

2. Write the chemical formula of a compound formed when X combine with Z

3. Name the types of bond formed when X and Y combine

8.

1. Why is the use of the balanced chemical equation so important in the chemical manufacturing industry? (2 Marks)

2. Study the following chemical reaction and answer the questions that follows

3KOH (eq) + FeCl3 (eq) →3KCl (eq) + Fe (OH) 3(s)

1. Write a net Ionic equation for the chemical equation above (1Marks)

2. What types of reaction is represented by the chemical equation

above? (1 Marks)

(c) Complete and balance each of the following equations

1. Mg(s) + Cl2(g) →

2. Zn(NO3)2(aq) + ZNaoH(aq) →

3. Hcl + CaO →

4. Hcl + Zn granules →

5. H₂SO₄ + NaHCO₃ →

SECTION C (30 Marks)

Answer two (2) questions from this section

9.

(a) Briefly explain the following observation about a sample of hard water

1. Water boil, If form white precipitate

2. After boiling water form scum

3. Sodium Carbonate makes the water completely soft

(b) With the aid of chemical equation briefly describe the following process

1. The removal of temporary hardness by boiling

2. The removal of permanent hardness of water by chemical means.

10.

1. Putin likes to use hard water to wash his clothes rather than soft water. His wife told him that hard water has a higher cost than soft water. Give reason to support Putin’s wife

2. Farida went to the laboratory and found four bottles on the bench each containing the mixture of the following. Bottle A contains alcohol and sand, bottle B contains Iodine and water, bottle C contains Iron fillings and powdered calcium chloride and bottle D contains Kerosene and water. With reason explain which method can be used to separate the mixture in each bottle above?

11. A form three students at Markaz Islamic Seminary had a task to mop the laboratory chamber, accidentally bees bite one of them on her hand. The technician advised me to apply ashes powder to the bite surface. Explain five importance of the process taking place on the skin surface to our daily life after applying ashes powder.

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