# In an experiment, a 2.514 g sample of calcium is heated in oxygen and the compound formed has a mass of 3.518 g. What is the empirical formula for the compound?

Jan 20, 2017

We get an empirical formula of $C a O$.

#### Explanation:

We can work out the individual masses of the elements in the binary compound, and we convert this to a molar quantity of each element:

$\text{Moles of calcium}$ $=$ $\frac{2.514 \cdot g}{40.1 \cdot g \cdot m o {l}^{-} 1} = 0.0627 \cdot m o l$

$\text{Moles of oxygen}$ $=$ $\frac{3.518 \cdot g - 2.514 \cdot g}{16.00 \cdot g \cdot m o {l}^{-} 1} = 0.0627 \cdot m o l$

We divide thru by the smallest molar quantity, and since there are equimolar quantities of metal and oxygen, the empirical formula is:

$C a O$.