Burning of paper is a______ change.

The burning of matchstick is an example for chemical reaction based on______

______ metal undergoes rusting.

The pigment responsible for browning of apples is______.

Which of the following factor induces electrolysis?

Dissolved gases like sulphur dioxide, nitrogen oxides in rain water causes______

______ is the basic material to manufacture urea.

Electrolysis of Brine solution gives ______ gases.

______ is a chemical substance which alters the speed of a chemical reaction.

______ is the enzyme responsible for browning of vegetables, fruits.

Define catalysis

What happens when an iron nail is placed in copper sulphate solution?

What is pollution?

Why photosynthesis is a chemical reaction?

Kumar is going to build a house. To purchase the iron rods required for construction, he visited an Iron & steel shop nearby. The seller showed him some Iron rods which are fresh and good. He also showed him little older Iron rods which are brownish in appearance. The price of fresh rods are costlier than the older ones, the seller also gave some offer to older ones. Kumar’s friend Ramesh advised him not to buy the cheaper rods.
a) Is Ramesh right in his suggestion?
b) Could you explain the reason for his suggestion?
c) What are the values shown by Ramesh?

Palanikumar is a Lawyer. He lives in a costly flat. Due to high rent, he wants to shift his residence to a place where he has a chemical industry nearby. There the rent is very cheap and the area is less populated also. Rajasekar, his son studying VIII does not like this and likes to go to some other place.
a) Is Rajasekar right in his attitude?
b) Why did he refuse to go there?
c) What are the values shown by Rajasekar?

Explain the role of yeast in making cakes and buns in a bakery?

Burning of fossil fuels is responsible for global warming. Justify the statement.

Explain how food items are spoiled by chemical reactions?

Explain the three types of pollution.

Explain any three conditions that is required for a chemical reaction to take place. Give example.