Question

D.A.V PUBLIC SCHOOL RANGAMATL, SINDRI
Std VIII (A+C) CHEMISTRY
HOME ASSIGNMENT FOR SUMMER VACATION
CHAPTER-6, Sources of energy & CHAPTER-7, Combustion
1. Answer the following questions-
1)
11)
V)
Rahul wants to separate the following materials as combustible and non-
combustible. Can you help him?
Charcoal, chalk, stone, iron rod, copper coin, straw, cardboard, glass,
paper, candle, wood.
How did a matchstick can be lighted by striking its tip on a rough surface?
Why does the flame of burning candle goes off when we blow over It strongly?
Why a paper cup filled with water does not catch fire easily on burning?
People usually keep Angethi/burning coal in their closed rooms during
winter season. Why is it advised to keep the door open?
Write the difference between spontaneous combustion and explosive
combustion?
Why water should not be used to extinguish fire caused by electric source
circult?
Which zone of candle flame is known as luminous zone and which zone is known
as non luminous zone and why?
The calorific values of petrol and CNG are 45000 kJ/kg and 50,000 kJ/kg,
VI)
VII)
VIII)
IX​

Answer 1

Answer:

Rahul wants to separate the following materials as combustible and non-

combustible. Can you help him?

Charcoal, chalk, stone, iron rod, copper coin, straw, cardboard, glass,

paper, candle, wood.

How did a matchstick can be lighted by striking its tip on a rough surface?

Why does the flame of burning candle goes off when we blow over It strongly?

Why a paper cup filled with water does not catch fire easily on burning?

People usually keep Angethi/burning coal in their closed rooms during

winter season. Why is it advised to keep the door open?

Write the difference between spontaneous combustion and explosive

combustion?

Why water should not be used to extinguish fire caused by electric source

circult?

Which zone of candle flame is known as luminous zone and which zone is known