CHEMISTRY FORM TWO MID TERM TEST SEPTEMBER 2023

FORM TWO MD-TERM TEST 2023

CHEMISTRY

TIME: 2:30HOURS                                                      AUGUST 2023

Instructions

1. This paper Consist of sections A and B with total of 10 questions

2. Answer all questions in both sections

3. All writings should be in blue/black ink

4. All diagrams should be drawn in pencil

5. Write your assessment number at the top right corner

SECTION A (20Marks)

1. For each of the items (i)-(x), choose the correct answer from among the given alternative and write its letter in the box provide.

i. The welders prefers to use non luminous flame for their work simply because

(A)It is available (B) it is easy to transport

(C) produce very hot flame (D) can be made by kerosene

ii. Spatula in the laboratory is used for scoping what types of substances? (A)Liquid and gases (B) solids and liquids

(C) Powdery and gases (D) Solids and powdery

iii. There are two particles inside the nucleus which one contributes the net change of that nucleus?

(A)Dalton (B)Protons (C) Electrons (D) Neutrons

iv. Why oxygen as one of the components of air Is unique?

(A)It has ability to burn (B) it support combustion

(C) it is diatonic gas (D) combine with carbon dioxide

v. Why it is necessary to boil drinking water?

(A) To make it tasteless (B) To remove impurities

(C) to kill micro-organism (D) To make it taste less

vi. How do chemists refer to a mixture of milk and water?

(B)Miscible solution (B) Suspension (C) Immiscible solution (D) Emulsion

vii. How can one prevent rusting in fragile instruments like camera?

(A)By galvanization (B) By using silica gel (C) By using oil (D) By using ethanol

viii. The oxidation state of metallic element is always

(A) Negative (B)Positive (C)Zero (D) Neutral

ix. Which of the following is not man-made product of applying chemistry?

(B) Sugar (B) Fertilizer (C) Milk (D) Vaccines

x. The atomic number of element R is 9 What is its electronic configuration? (A)2:4:3 (B) 2:5:2 (C) 2: 7 (D) 2:6:1

2. (a) Match each item in List A with a correct response in List B by writing the letter of the correct response below the corresponding item number in the table provided

LIST A	LIST B
i. Spirit in water	A. Winnowing
ii. Sodium Chloride in water	B. Layer separation
iii. Oil in sunflower	C. Fractional distillation
iv. Ammonium Chloride crystals in sand	D. Picking
v. Maize and husk	E. Solvent extraction
	F. Sublimation
	G. Decantation
	H. Evaporation

SECTION B: (80 MARKS)

3. (a) Mrs. Msema kweli was addressing the villagers about use of water for economic values. What 4 values will she tell the villagers

(b) Is an air a mixture or a compound? Give 4 reasons

4. (a) Do your think there is any reasons for providing first Aid to the Victim? If yes give four reasons.

(b) State the uses of the following items in first aid Kit.

(i) The pair of scissors

(ii) The whistle

(iii) Petrolleum jelly

(iv) Sterile gauze

5. (a)State three sub- atomic particles and their respective charge.

(b)State the four modification of Dalton`s atomic theory

(c)Draw and write the electronic configuration for the atoms having the following atomic numbers.

(i) 4Be

(ii) 14Si

6. (a)Distinguish the following substances.

i. Homogenous mixture from heterogeneous mixture.

ii. Miscible from immiscible liquids.

iii. Saturated from unsaturated solution.

(b) Give two chemical tests for pure water

7. (a) Asha want to select a good fuel for domestic uses in her home what things should she considered? (Mention six (6)

(b)Classify the following fuel either primary or secondary fuel.

(i) Coke

(ii) Crude oil

(iii)Kerosene

(iv)Natural gas

8. (a)What properties of hydrogen gas that made it to be used in the following?

i. As a fuel

ii. To fill weather balloons

iii. Manufacture of hydrochloric acid

iv. Manufacture of margarine

(b) Environmental pollution in most of rural areas in Tanzania is caused by using charcoal and firewood as a fuel. What will be the two alternative source of energy, they supposed to use for environmental conservation? (give reason for each)

(c) Why fossil fuels are referred to as non-renewable energy resources? (Give two reasons)

9. (a)You are provided with the following atoms, for each fill the informations below:-

(i) 35.5Cl

protons = Neutrons=

Electrons=

(ii) 1H

protons = Neutrons=

Electrons=

(b) Define the following

i. Atom

ii. Energy

iii. Atomic number

iv. Isotopes

10. a)i. What do you understand by the word “Relative atomic mass”?

ii). Carbon has main isotopes, 126 C and 14 6C with relative abundances 98.89% and1.11% respectively. Calculate the relative atomic mass of Carbon.