Diethyl ether is produced from ethanol according to the following equation:

2CH3CH2OH(l) → CH3CH2OCH2CH3(l) + H2O(l)

100. g of ethanol reacts to produce 66.0 g of ether.

11) What is the theoretical yield?

2 moles of ethanol => 1 mol of ether

100g of ethanol  = 100/ 46 moles --> 50/46 moles of ether = 50/46 * 74 = 80.4347 g 

12) What would be the % yield?

% yield = 82.05%