Give the appropriate term defined by the statement given: The formula that represents the simplest ratio of the various elements present in one molecule of the compound.

Find the empirical and molecular formula of an organic compound from the data given: C = 75.92%, H = 6.32% and N = 17.76%. The vapour density of the compound is 39.5

[C = 12, H = 1, N = 14]

Na₂SO₄ + Pb(NO₃)₂ ⟶ PbSO₄ + 2NaNO₃. When excess lead nitrate solution was added to a solution of sodium sulphate, 15.15 g of lead sulphate were precipitated. What mass of sodium sulphate was present in the original solution.

[H = 1 ; C = 12 ; O = 16 ; Na = 23; S = 32 ; Pb = 207]

From the equation : (NH₄)₂ Cr₂O₇ ⟶ Cr₂O₃ + 4H₂O + N₂ Calculate :

(i) the vol. of nitrogen at STP, evolved when 63 g. of ammonium dichromate is heated.

(ii) the mass of Cr₂O₃ formed at the same time.

[N = 14, H = 1, Cr = 52, O = 16]