A 0.24 g sample of a 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.

How many atoms are present in H₂SO₄?

Name a diatomic gas.

Calculate formula unit mass of CaCl₂.

How many atoms are there in exactly 12 g of carbon?

Give Latin names for sodium & mercury.

What is molecular mass?

What name is given to the number 6.023 × 10²³?

What term is used to represent the mass of 1 mole molecules of a substance?

Who gave law of conservation of mass?

Give one relevant reason why scientists chose 1/16 of the mass of an atom of naturally occurring oxygen as the atomic mass unit.

What is the atomicity of Argon?

What are polyatomic ions? Give two examples.

What is the number of electrons in Mg atom and Mg²⁺ ion?

‘Atoms of most elements are not able to exist independently.’ Name two atoms which exist as independent atoms.

Name the element which is used as the reference for atomic mass.

Which organisation approves the names of elements all over the world ? Write the symbol of gold.

Define law of constant proportion.

Define law of conservation of mass.

Name the scientist who laid the foundation of chemical sciences. How?

Calculate the molar mass of the following substances: (a) Ethyne, C₂H₂ (b) Sulphur molecule, S₈ (c) Phosphorus molecule, P₄ (Atomic mass of phosphorus = 31) (d) Hydrochloric acid, HCl (e) Nitric acid, HNO₃

Give the names of the elements present in the following compounds: (a) Quick lime (b) Hydrogen bromide (c) Baking powder (d) Potassium sulphate

Write the chemical formulae of the following: (a) Magnesium chloride (b) Calcium oxide (c) Copper nitrate (d) Aluminium chloride (e) Calcium carbonate

What are polyatomic ions? Give examples.

When 3.0 g of carbon is burnt in 8.00 g of oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?