Question

What is the % yield of CO2 if 10g of CO produces 12.8 g CO2? 2CO + O2 → 2CO2

Answer 1

The % yield is 81.5 :DDDDDD

Answer 2

Moles CO = 10.0 g / 28.01 g/mol = 0.357 
the ratio between CO and CO2 is 2 : 2 ( or 1 : 1) so we would get 0.357 mole of CO2 ( 100% yield) 

mass CO2 = 0.357 mol x 44.0098 g/mol = 15.7 g ( theoretical yield) 

% yield = 12.8 x 100 / 15.7 = 81.5

Hope this helps.