How much calcium oxide is obtained by heating 82 g of calcium nitrate? Also find the volume of NO₂ evolved:

2Ca(NO₃)₂ ⟶ 2CaO + 4NO₂ + O₂

The equation for the burning of octane is:

2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 18H₂O

(i) How many moles of carbon dioxide are produced when one mole of octane burns?

(ii) What volume at S.T.P. is occupied by the number of moles determined in (i)?

(iii) If the relative molecular mass of carbon dioxide is 44, what is the mass of carbon dioxide produced by burning two moles of octane?

(iv) What is the empirical formula of octane?

Silicon (Si = 28) forms a compound with chlorine (Cl = 35.5) in which 5.6 g of silicon combines with 21.3 g of chlorine. Calculate the empirical formula of the compound.

O₂ is evolved by heating KClO₃ using MnO₂ as a catalyst.

2KClO₃ $\xrightarrow{\text{MnO}_2}$ 2KCl + 3O₂

(a) Calculate the mass of KClO₃ required to produce 6.72 litre of O₂ at STP.

(atomic masses of K = 39, Cl = 35.5, 0 = 16).

(b) Calculate the number of moles of oxygen present in the above volume and also the number of molecules.

(c) Calculate the volume occupied by 0.01 mole of CO₂ at STP.