Let us first illustrate the reaction of Copper and Oxygen
• 2Cu +O2 → 2CuO
ratioon > 2 : 1
step 1 : determine moles of Cu and O2 .
(i) Moles Cu = mass Cu/Molar Mass Cu
= 63.6 g/ 63.546g/mol
=1.001 mol
(ii) moles O2 = mass Oxygen/Molar Mass Oxygen
= 71.6/32
= 2.238mol
Step 2 :
Experimental moles of Cu : O2
1.001moles : 2.238moles
take note that excess reactant is O2 and limiting reactant is Cu
Therefore moles of Oxygen that reacted = 1/2 moles of Cu
= 1/2 * 1.001 = 0.5moles
Mass of Oxygen reacted =0.5* 32 (oxygen Molar mass)
=16.01g
This means that 16.01 grams of Oxygen reacted , this value is not in the options provi
