Question

class 9 icse chemistry chapter 2 chemical changes amd reaction all mcq question with answers

Answer 1

Explanation:

1. Zinc is __ when it is hot.

A. Yellow

B. White

C. Red

D. Green

2. CuSO4 is a ___ soln

A. Green

B. Blue

C. Yellow

D. None

Answer 2

Chemical changes and reactions contain topics pertaining to various chemical reactions and their mechanisms.

• Some of the questions that can be asked under this chapter are:

• Why should we learn chemical reactions?

• Chemical reactions enable one to understand how two or three molecules react with each other and the products that are formed during the reaction.

• What to mention in a reaction?

• A reaction consists of a reactant and consecutive products. For a reaction to occur, a catalyst or physical factors like pressure, temperature, etc, is to be mentioned.

• What are the important points to remember while writing a chemical reaction?

• When writing a chemical reaction, the first step is to understand the type of reaction that is whether it's a hydrogenation reaction or dissociation reaction, etc. Based on the type of reactions, the catalyst and physical factors will differ. Once the type of reaction is understood, the next step is to balance each reactant and product. Ensure to write a forward arrow between reactants and products to indicate the reaction is moving forward.