1.375 g CuO was reduced by hydrogen and 1.098 g Cu was obtained. In another experiment 1.179g of Cu was dissolved in nitric acid and the resulting copper nitrate was converted into CuO by ignition. The weight of CuO formed was 1.476g. Show that these results prove the law of constant composition

Weight of copper oxide obtained by treating 2.16 g metallic copper with nitric acid and subsequent ignition was 2.70 g. In another experiment, 1.15 g of copper oxide on reduction yielded 0.92 g of copper. Show that these results illustrate the law of definite proportions.

A sample of 1.0g of solid Fe_(2)O_(3) of 80% purity is dissolved in a moderately concentrated HCl solution which is reduced by zinc dust. The resulting solution required 16.7mL of a 0.1M solution of the oxidant. Calculate the number of electrons taken up by the oxidant.

A 0.276 g impure sample of copper ore is dissolved and Cu^(2+) is titrated with KI solution. I_(2) liberated required 40 mL of 0.1 M Na_(2) S_(2) O_(3) solution for titration. What is the % of impurities in the ore ?

Three conductivity cells A, B and C containing solutions of zinc sulphate, silver nitrate and copper sulphate respectively are connected in series. A steady current of 1.5 amperes is passed through them until 1.45 g of silver is deposited at the cathode of cell B. How long did the current flow ? What mass of copper and what mass of zinc got deposited in their respective cells ? (Atomic mass : Zn = 65.4 u, Ag = 108 u, Cu = 63.5 u)

2g of benzoic acid ( C_6H_5COOH ) is dissolved in 25g of benzene show depression in freezing point equal to 1.62K. Molar depression constant for benzene, K_f =4.9K kg mol^-1 . What is percentage association of acid if it forms a dimer in solution?