Calculate...?

Question

Calculate the grams of O per one gram of sulfur in sulfur dioxide and sulfur trioxide and use the data to illustrate the Law of Multiple Proportions
explain and show please?

Answer 1

Sulphur Dioxide (SO2)
The ratio of S : O :: 1 : 2
Moles S = 1 /32 = 0.03125
Moles O = 0.03125 x 2 = 0.0625
Mass O = 0.0625 x 16 = 1 gram

Sulphur Trioxide (SO3)
The ratio of S : O :: 1 : 3
Moles S = 1/32 = 0.03125
MolesO = 0.03125 x 3 = 0.09375
Mass O = 0.09375 x 16 = 1.5 grams

Law of Multiple Proportions
If two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.

Another way to say this is:

A law proposed by Dalton which states that when elements combine, they do so in the ratio of small whole numbers. For example Sulphur and oxygen react to form SO2 or SO3, but not SO2.8.

It will be noticed from above :-
SO2 : SO3 :: 1 g (O) : 1.5 g (O)
So the proportions by mass are :-
SO2 : SO3 :: 2 : 3