How many atoms of He are present in 52 \(\mu\) of He?

5

(a)

A lady purchases a ring from a jeweller with diamonds embedded into it. The jeweller tells that total diamond used in the ring is five carat. How much weight he should subtract from the weight of the ring to get the weight of gold?

5

(a)

Copper sulphate crystals contain 25.45% Cu and 36.07% H₂O. If the law of constant proportions is true then calculate the weight of Cu requires to obtain 40g of crystalline CuSo₄.

5

(a)

Commercially available sulphric acid contains 93% acid by mass and has density of 1.84 gm^-1.Calculate the molarity of the solution

5

(a)

A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L (measured at STP) of this welding gas is found to weigh 11.6 g. Calculate (i) empirical formula, (ii) molar mass of the gas, and (iii) molecular formula.

5

(a)

Arrange the following in order of their increasing masses in gram one gram of iron

5

(a)

A compound made up of two elements A and B has A = 70%, B = 30%. Their relative number of moles in the compound are 1.25 and 1.88. Calculate molecular formula of the compound, if its molecular mass is found to be 160.

5

(a)

The density of the water at room temperature is 0.1 g / mL. How many molecules are there in a drop of water if its volume is 0.05 mL?

5

(a)