Oxygen contains 90% O¹⁶ and 10% O¹⁸. Its atomic mass is

(1) 17.4

(2) 16.2

(3) 16.5

(4) 17

The total number of electrons present in 1.6 gm. of methane is [IIT 1976; Roorkee 1985; CPMT 1987, 92]

(1) 6.02 × 10²³

(2) 6.02 × 10²²

(3) 6.02 × 10²¹

(4) 4.02 × 10²⁰

KClO₃ on heating decomposes to KCl and O₂. The volume of O₂ at STP liberated by 0.1 mole KClO₃ is

1. 4.36 L

2. 3.36 L

3. 2.36 L

4. None of these

At S.T.P. the density of CCl₄ vapour in g/L will be nearest to [CBSE PMT 1988]

(1) 6.84

(2) 3.42

(3) 10.26

(4) 4.57

4.4 g of an unknown gas occupies 2.24 litres of volume at NTP. The gas may be: 

The number of gram molecules of oxygen in 6.02 × 10²⁴ CO molecules are:

1. 10 g molecules

2. 5 g molecules

3. 1 g molecules

4. 0.5 g molecules

The mass of carbon present in 0.5 mole of K₄[Fe(CN)₆] is:

1. 1.8 g

2. 18 g

3.  3.6 g

4.  36 g

The number of moles of BaCO₃ which contains 1.5 moles of oxygen atoms is:

1. 0.5

2. 1

3. 3

4. 6.02 ×10²³

The oxide of metal contains 40% by mass of oxygen. The percentage of chlorine in the chloride of the metal is

1. 84.7

2. 74.7

3. 64.7

4. 44.7

The empirical formula of an organic compound containing carbon and hydrogen is CH₂. The mass of one litre of this organic gas at STP  is exactly equal to that of one litre of N₂ at STP. Therefore, the molecular formula of the organic gas is:

1. C₂H₄

2. C₃H₆

3. C₆H₁₂

4. C₄H₈