English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

What is the mass of 0.2 mole of oxygen atoms?

What is the mass of 0.5 mole of water molecules?

Why are lysosomes known as suicide bags?

Write down two main functions of (b) Lysosome.

"Lysosomes are known as suicide bags". Why?

Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y 􀁯 P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following  statements concerning X, Y and P are correct ?

1. P is a compound
2. X and Y are compounds
3. X and Y are elements
4. P has a fixed composition

State one instance where water undergoes a physical change and one in which it undergoes a chemical change.

Classify the following as physical or chemical changes :

1. Cooking of food
2. Boiling of water
3. Cutting of trees
4. D0issolving salt in water
5. Digestion of food
6. Melting of ice

Classify the following as physical or chemical change :

Formation of curd from milk

Classify the following as physical or chemical change :

Condensation of steam

Classify the following as physical or chemical change :

Growth of a plant

Classify the following as physical or chemical changes :

Breaking of a glass tumbler

Separate the following into physical and chemical changes :

Sublimation of a solid, Decomposition of water into hydrogen and oxygen by passing electric current, Formation of clouds, Making a fruit salad from raw fruits, Dissolving carbon dioxide in water

Which of the following are physical changes and which are chemical changes?

Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.

What is a physical change ? Give two examples of physical changes.

What is a chemical change ? Give two examples of chemical changes.

Give the main differences between physical changes and chemical changes.

Which of the following are physical changes and which are chemical changes ?

Which of the following are physical changes and which are chemical changes ?

Freezing of water

Which of the following are physical changes and which are chemical changes ?

 Rusting of iron