Calculate the percent of oxygen in potassium chlorate. This is known as the theoretical yield. Include % and round to the nearest whole number.

Answer 1

Let me correct you. It is NOT known as theoretical yield. It is known as percent composition.
% O = (grams oxygen/grams KClO3)*100 = ?
The easy way to do this is to use atomic and molar masses; i.e., atomic mass O = 16 and 3*16 = 48. Molar mass KClO3 is 122.6 (you need to confirm that).
%O = [(3*16)/122.6]*100 = ?
Post your work if you have additional questions.