mole concept

2 g of oxygen contains number of atoms equal to that in

• 0.5 g of hydrogen

• 4 g of sulphur

• 7 g of nitrogen

• 2.3 g of sodium

Mole fraction of A in H2O is 0.2 . The molality of A in H2O is :

• 13.9

• 15.5

• 14.5

• 16.8

The percentage composition of carbon by mole in methane is :

• 80%

• 25%

• 75%

• 20%

The number of atoms in 4.25 g of NH3 is approximately

• 1 x 10 ²³

• 2 x 10 ²³

• 4 x 10 ²³

• 6 x 10 ²³

Haemoglobin contains 0.33% of iron by weight. The molecular weight of Haemoglobin weight of Haemoglobin is approximately 67200 . The number of iron atoms ( At. wt of Fe= 56) present in one molecule of Haemoglobin is

• 6

• 1

• 4

• 2

The total number of protons in 10 g of calcium carbonate is

• 1.5057 x 10²⁴

• 2.0478 x 10²⁴

• 3.0115 x 10²⁴

• 4.0956 x 10²⁴

The mass of a molecule of water is

• 3 x 10^-26 kg

• 3 x 10^-25 kg

• 1.5 x 10^-26 kg

• 2.5 x 10^-26 kg

4.4 g of an unknown gas occupies 2.24 L of volume at standard temperature and pressure. The gas may be

• Carbon dioxide

• Carbon monoxide

• Oxygen

• Sulphur Dioxide

one litre of a gas at STP weigh 1.16 g it can possible be

• C₂H₂

• CO

• O₂

• CH₄

12 g of Mg (at. mass 24) will react completely with acid to give

• One mole oh H₂

• 1/2 mole of H₂

• 2/3 mole of O₂

• Both 1/2 mol of H₂ and 1/2 mol of O₂