Question

Calculate the empirical formula for each compound.
2.677 g Ba, 3.115 g Br

Answer 1

Answer:

Element  - Ba

Moles = mass / (molar mass)

$\frac {2.677g}{(137.327 g/mol)} = 0.0195 mol$

Mole ratio

$\frac{0.019}{0.0195} = 1$

Element  - Br

Moles = mass / (molar mass)

$\frac {3.115g}{(79.904 g/mol)} = 0.0390 mol$

Smallest is 0.0195 mol

Mole ratio

$\frac {0.0390}{0.0195} = 2$

Empirical formula

So, The empirical formula is $Ba_1 Br_2$

We divide mass by molar mass to get moles in the first step and then we select the least answer from it and divide them all. The whole number which we get becomes the subscript of the Empirical formula.