A 230 g sample of a compound contains 136.6 g of carbon. 26.4 g of hydrogen, and 31.8 g of nitrogen. The rest is oxygen. What is the mass percent of oxygen in the compound?

1 Answer
Apr 13, 2016

Answer:

#((230-136.6-26.4-31.8)*g)/(230*g)# #xx# #100%# #=# #??%#

Explanation:

The mass of oxygen in the #230# #g# sample is simply that mass that is not #C#, #H#, or #N#. So I simply subtract from the starting mass and the balance must be oxygen.

In fact there are few ways that an analyst can measure oxygen. Typically, a sample containing #C,H,N,O# will be presented, and the percentage #C#, #H#, #N# will be reported. The percentage #O# is the percentage not accounted for is assumed to be oxygen.