MEDIUM
8th Kerala Board
IMPORTANT
Earn 100

What could be the reason for storing certain medicines and chemicals in brown bottles? Think of it. 

Important Questions on Chemical Changes

MEDIUM
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 1

Assess the chemical reactions given below and answer the questions.

Calcium carbonate + heat → Calcium oxide + Carbon dioxide 

Calcium oxide + water → Calcium hydroxide + heat 

a) Mention the reactants and products in each case. 

b) Which among these are endothermic? Which one is exothermic? 

EASY
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 2
Identify the energy change involved and write down what type of chemical reaction takes place in glowing of a fire fly.
MEDIUM
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 2
Identify the energy change involved and write down what type of chemical reaction takes place in plating a copper ring with gold.
EASY
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 2
Identify the energy change involved and write down what type of chemical reaction takes place in Burning of fuels.
MEDIUM
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 3
A student tries to plate an iron nail with copper. Draw its arrangement by selecting the required materials from the list given below. Silver nitrate, iron nail, copper sulphate, silver rod, copper rod, silver plate, iron sulphate, battery, wire, water, beaker. 
MEDIUM
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 5
Classify the following into physical changes and chemical changes. 
1. Melting of ice.
2. Heating magnesium in water.
3. Silver bromide kept exposed to sunlight.
4. Change happening to soda water on opening its bottle.
MEDIUM
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Let us assess>Q 6
Give an example each for exothermic and endothermic reactions.
HARD
8th Kerala Board
IMPORTANT
Science for Class 8 - Part 1>Chapter 6 - Chemical Changes>Extended activities>Q 1
Making a volcano
Heap up some ammonium dichromate powder on a tile. Deposit on it the chemical present on a match stick, and ignite. Write down the changes happening there.
Change in colour _____
Change in amount _____
Exchange of energy ____