Question

Question #0b65e

Answer 1

It will contain 2.04 g of sodium.

We can work out the empirical formula of sodium bromide by writing down the ratio by which they combine in grams:

Na : Br

= 22.34 : 77.66

( I got 77.66 by subtracting 22.34 from 100 as it is a % age)

Now we get the ratio in moles by dividing each by the mass of I mole .

(`A_r [Na] = 23` `A_r [Br] = 80`)

= 22.34/23 : 77.66/80

= 0.97 : 0.97

= 1 : 1

So the empirical formula is NaBr.

The `M_r` of sodium bromide is therefore 23 + 80 = 103.

This means that 103g of sodium bromide must contain 23g of sodium.

So 1g of sodium bromide must contain 23/103 g of sodium.

So 9.13 g of sodium bromide must contain `(23)/(103)` x 9.13 = 2.04 g of sodium.