washing soda contains 43.4%sodium mass and 45.3% oxygen mass and one more element.If the molar mass of washing soda is 105.99g/mol, identify the other element .

Question

I need help with this grade 11 chemistry question.

Answer 1

100% - 43.4% - 45.3% = 11.3%

So the other element is 11.3% by mass. 

11.3% x 105.99 g = 11.98 g

This is closest to the atomic mass of carbon (C).

The compound would be Na2CO3.