A 58.44-g sample of sodium chloride contains 35.45 g of chlorine, with sodium being the only other element. How many grams of sodium are in a sample of 13.74 g of sodium chloride?

Answer 1

The ratio of sodium to total mass is constant, so
x/13.74 = (58.44-35.45)/58.44

Answer 2

I want to point out that I don't like the way the problem is stated. The sample contains 35.45 g Cl or 35.45 g chloride but not 35.45 g chloRINE. This is a common error made by students and teachers alike. I have seen it in texts, also but that doesn't make it any more correct.