English Medium इयत्ता ९ - CBSE Question Bank Solutions

Try segregating the things around you as pure substances or mixtures.

Explain the following giving an example.

Pure substance

Which of the following are chemical changes?

1. Growth of a plant
2. Rusting of iron
3. Mixing of iron fillings and sand
4. Cooking of food
5. Digestion of food
6. Freezing of water
7. Burning of candle

Define the atomic mass unit.

If one mole of carbon atoms weighs 12 gram, what is the mass (in gram) of 1 atom of carbon?

Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, atomic mass of Na = 23 u, Fe = 56 u)?

A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

Calculate the molar mass of the following substance: 

Ethyne, C₂H₂

Calculate the molar mass of the following substance: 

Phosphorus molecule, P₄ (atomic mass of phosphorus = 31)

Calculate the molar mass of the following substance: 

Sulphur molecule, S₈

Calculate the molar mass of the following substance: 

Hydrochloric acid, HCl

Calculate the molar mass of the following substance: 

Nitric acid, HNO₃

What is the mass of 1 mole of nitrogen atoms?

What is the mass of 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?

What is the mass of 10 moles of sodium sulphite (Na₂SO₃)?

Convert into mole.

12 g of oxygen gas

Convert into mole.

20 g of water

Convert into mole.

22 g of carbon dioxide

What is the mass of 0.2 mole of oxygen atoms?

What is the mass of 0.5 mole of water molecules?