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?

1 Answer
Jan 20, 2017

Answer:

We get an empirical formula of #CaO#.

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:

#"Moles of calcium"# #=# #(2.514*g)/(40.1*g*mol^-1)=0.0627*mol#

#"Moles of oxygen"# #=# #(3.518*g-2.514*g)/(16.00*g*mol^-1)=0.0627*mol#

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

#CaO#.