12dm3 ethene reacts with steam to make 18.4g ethanol. find the percentage yield

% yield = 74.35

Given

12 dm³ ethene = 12 L

18.4 g ethanol(actual)

Required

The percentage yield

Solution

Reaction

C₂H₄(g) + H₂O(g) ⇒ C₂H₅OH(g)

Assume at STP, 1 mol gas = 22.4 L

mol ethene :

= 12 L : 22.4 L

= 0.538

From equation, mol ratio C₂H₅OH : C₂H₄ = 1 : 1, so mol C₂H₅OH = 0.538

Mass Ethanol (MW=46 g/mol) ⇒ theoretical

= 0.538 x 46

= 24.748 g

% yield = (actual/theoretical) x 100%

% yield = (18.4/24.748) x 100%

% yield = 74.35

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.