Question

The percentage composition of Sodium phosphate is 42.1% Sodium, 18.9% Phosphorus and 39% Oxygen. If its molecular weight is 164 calculate its molecular formula. [Na = 23, P = 31, O = 16]

Answer 1

Answer:

We take percentage composition so that one can check the purity of a given sample by analysing the data, so to find the percentage composition we can calculate it by the formula which is as follows:

Mass % of an element = MassofthatelementinthecompoundMolarmassofthecompound×100

Now considering data given to us in the question we can say that,

Element Sodium has percentage composition and its atomic weight is

Now calculating its relative number of atoms which is

42.123=1.83

Now its simplest ratio will be:

18.90.61=3

Now for Phosphorus its percentage composition and its atomic weight is

Now calculating its relative number of atoms which is

18.931=0.61

Now its simplest ratio will be:

0.610.61=1

Now proceeding to oxygen its percentage composition and its atomic weight is

Now calculating its relative number of atoms which is

18.931=2.44

Now its simplest ratio will be:

2.440.61=4

So by concluding the data simplest form of sodium, phosphorus and oxygen are and so we get our empirical formula as Na3PO4