Question

a 10.99g sample of NaBr contains 22.34% Na by mass. Considering the law of constant composition (define proportions), how many grams of sodium does a 9.77g sample of sodium bromine contain?

Answer 1

Given :

A 10.99 g sample of NaBr contains 22.34% Na by mass.

To Find :

How many grams of sodium does a 9.77g sample of sodium bromine contain.

Solution :

By law of constant composition , in any given chemical compound, the elements always combine in the same proportion with each other.

Therefore , percentage of Na by mass in NaBr will be same for every amount .

Percentage of Na in 9.77 g NaBr is 22.34 % too .

Gram of Na = $9.77\times \dfrac{22.34}{100}=2.18\ g$ .

Hence , this is the required solution .