Consider the following reaction between Cyclohexene and hydrogen bromide: Cycloh
ID: 1065682 • Letter: C
Question
Consider the following reaction between Cyclohexene and hydrogen bromide: Cyclohexene (C_6H_12): molecular weight = 82.14 g/mol: density 0.811 g/mL HBr acid: 30% by weight solution (30 grams/100 mL) How many grams of Cyclohexene are involved in this reaction? How many grams of hydrobromic acid arc involved in this reaction?_ How many moles of Cyclohexene arc involved?__ How many moles of hydrobromic acid are involved? Which compound is the limiting reagent? What is the maximum number of moles of product that can form ? What is the maximum number of grams of products that can form? What would be the percent yield if 25 grams of product are isolated?Explanation / Answer
ANSWER
(A) mass of cyclohexane = dnsity X volume = 0.811 X 40 = 32.44g
(B) HBr = 30%. It implies 30g of HBr is present in 100mL of solution. In the reaction we have taken 100mL of HBr hebce mass of HBr = 30g
(C) Number of moles = mass / Molecular mass = 32.44 / 82.14 = 0.39 moles
(D) Moles of HBr = 30.0 / 80.9 = 0.37 moles
(E) One mole of cyclohexane reacts with one mole of HBr, hence 0.39 moles of Cyclohexane will react with 0.39 moles of HBr. But only 0.37 moles of HBr are present in the reaction mixture. So HBr will limitt the reaction. HBr is limitting reagent.
(F) The amount of product formed is determined by the limitting reagent. Hence meximum amount of product that can form is 0.37 moles.
(G) mass of product formed = number of moles X molar mass = 0.37 X 163.0 = 60.31 g
(H) % yeild = (mass of product isolated / meximum mass expected ) X 100 = (25 / 60.3) X 100 = 41.6 %.