Atoms and Molecules

What is formula unit mass? How is it different from molecular mass?

What is the ratio by mass of combining elements in H₂O, CO₂ and NH₃?

What is meant by atomic mass, gram atomic mass of an element? Why is the mass have different expressions i.e., 'u' and 'g'?

Consider the compound calcium carbonate (CaCO₃).

 (a) Name the elements present in calcium carbonate.

 (b) Calculate its formula unit mass. (Atomic masses: Ca = 40u, C = 12u, O = 16u)

(c) If a sample of calcium carbonate contains 6.022 × 10²³ formula units, what would be its mass in grams?

Give the atomicity of phosphorous and nitrogen.

What is atomic mass unit?

Explain law of constant proportion.

Define valency and give the valency for the following elements:

What is polyatomic ton? Give one example.

Give the Latin name for sodium, potassium, gold and mercury.

Write down the formula for:

Copper nitrate, calcium sulphate and aluminium hydroxide.