Question

Calculate the percentage composition of Na and C in Na₂CO₃ [Relative atomic mass of O = 16, Na = 23, C = 12]

Answer 1

percentage of Na ={ 46\106}100

and of C=(12\106)100

Answer 2

Percentage composition of Na = 43.4%

Percentage composition of C = 11.3%

Explanation:

Na₂CO₃ [Relative atomic mass of O = 16, Na = 23, C = 12]

Molar mass of Na₂CO₃  = twice atomic mass of Na + atomic mass of C + thrice atomic mass of O

= (2 * 23) + 12 + (3 * 16) = 46 + 12 + 48

= 106

Percentage composition of Na = Mass of Na in the compound / total mass of compound * 100  

= 46 / 106 * 100

= 0.4339 * 100

= 43.4%

Percentage composition of C = Mass of C in the compound / total mass of compound * 100  

= 12 / 106 * 100  

= 0.1132 * 100  

= 11.3%