Question

define law of gaseous volume

Answer 1

When gas combine or produce in a chemical reaction they do so in a simple ratio by volume providing all gas are at same temperature and pressure

Answer 2

Law of combining volumes states that 'gases combine with each other in simple proportions by volume'. When gases react in volumes, they have a simple ratio to one another and also to the volume of the product formed, if they are gases. (under similar conditions of temperature and pressure).

 

Examples: 

H2 (g) + Cl2(g) -------->  2HCl (g)

1 volume of H2 gas combines with 1 volume of Cl2 gas forms 2 volumes of HCl gas. The ratio by volume of gases is 1:1:2.

So 20 cm3 of hydrogen reacts with 20 cm3 of chlorine ==> 40 cm3 of hydrogen chloride (2 x20)

 

N2(g) + 3H2(g) ==> 2NH3(g)

1 volume of nitrogen gas reacts with 3 volumes of hydrogen gas to produce 2 volumes of ammonia gas. The ratio by volume of gases is 1:3:2.

So 50 cm3 nitrogen reacts with 150 cm3 hydrogen (3 x 50) ==> 100 cm3 of ammonia (2 x 50)