Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol^–1.

Classify each of the following on the basis of their atomicity.

(a) F₂ (b) NO₂

(c) N₂O (d) C₂H₆

(e) P₄ (f) H₂O₂

(g) P₄O₁₀ (h) O₃

(i) HCl (j) CH₄

(k) He (l) Ag

You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without tasting?

Verify by calculating that

(a) 5 moles of CO₂ and 5 moles of H₂O do not have the same mass.

(b) 240 g of calcium and 240 g magnesium elements have a mole ratio of 3:5.

Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)

(a) CaCO₃

(b) MgCl₂

(c) H₂SO₄

(d) C₂H₅OH

(e) NH₃

(f) Ca(OH)₂