31) How many grams of S are required to produce 100 moles and 100 gm H₂SO₄ separately?

32) An alloy has Fe, Co and Mo equal to 71%, 12% and 17% respectively. How many cobalt atoms are there in a cylinder of radius 2.5 cm and length of 10 cm? The density of alloy is 8.2 gm⁄mL. (Atomic weight of Co = 58.9)

33) What is the molecular weight of a substance, each molecule of which contains 9 C atoms, 13 H atoms and 2.33 x 10⁻²³ gm of other components?

34) K−40 is a naturally occurring radioactive isotope having natural abundance 0.012% of potassium isotopes. How many K−40 atoms do you ingest by drinking one cup of whole milk containing 370 mg K?

35) P and Q are two elements which form P₂Q₃ and PQ₂. If 0.15 mol of P₂Q₃ weighs 15.9 gm and 0.15 mol of PQ₂ weighs 9.3 gm, what are the atomic weights of P and Q respectively?