8th Standard Science
Chemistry | UNIT- 10 Changes around us
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8th Chemistry UNIT 10 Changes around us, 8th Science, Physics UNIT-2 Force and Pressure July Month Assignment , 8th Science July Month assignment, TN 8th Standard Science UNIT-2 Force and Pressure, UNIT- 10 Changes around us and UNIT- 17 Plant Kingdom July Month Assignment Download PDF. 8th Assignment 2 Unit2 July Month Assignment.
ASSIGNMENT
Class: 8 Subject: Science(Chemistry)
Part A
UNIT- 10 Changes around us
I. Choose the correct answer.
1. What kind of changes take place in the following?
i) sugar dissolved in water
ii) strong heating of sugar
a) i) and ii) - Physical change
b) i) and ii) - Chemical change
c) i) - Physical change, ii) - Chemical change
d) i) - Chemical change, ii) - Physical change
2. In which of the following, new products are formed?
a) Physical change
b) Chemical change
c) Reversible change
d) None of the above
3. The chemicals in the head of a matchstick
a) Red phosphorous
b) White phosphorous
c) Potassium chlorate and antimony trisulphide
d) Sliver nitrate
4. In which state, sodium chloride and silver nitrate undergo chemical
changes
a) solid - liquid
b) liquid- solid
c) solid-liquid
d) liquid-liquid
5. The chemical reactions proceed only by the passage of electricity in
a) Electrolysis
b) Conductors
c) Electroplating
d) Electricity
Part B
II. Short Answer.
1. What happens when quick lime comes into contact with water?
2. What is Exothermic and Endothermic Reaction?
3. When a small amount of lead nitrate taken in a dry test tube and
heated gently over a flame, what changes would occur?
Part-C
III. Answer in detail.
1. a) Explain the electrochemical reaction and thermo chemical reaction.
b) Write down the chemical changes in the following:
i) Spoilage of food and vegetables
ii) Rancidity of fishes and meat
iii) Apples and fruits turn brown when we cut.
Part-D
IV. Activity
Categorize the given chemical substances and write their effects in the given
table.
Methane, detergents, carbon dioxide, plastics, oil spillage, oxides of sulphur,
solid wastes, dyes, herbicides, carbon monoxide, oxides of nitrogen,
pesticides, chlorofluorocarbons.
| Types of Pollution | Chemical Substances | Effects |
|---|---|---|
| Air Pollution | ||
| Water Pollution | ||
| Land Pollution |
