Consider the reaction (formation of 1,2-dibromocyclohexane from cyclohexene and bromine). a)If 4.75 ml of ?

Question

cyclohexene is reacted with 7.04g of bromine , which is the limiting reagent?

b) What is the theoretical yield of product in grams?

Answer 1

First, let's write the equation for the chemical reaction:

C6H10 + Br2 -> C6H10Br2

It can be seen that the molar ratio is one-to-one for the products and reactants. In order to determine the limiting reagent, we need to calculate how many moles of each is being added. The density of bromine is 3.1028 g / cm^3. The density of cyclohexene is 0.8111 g / cm^3. The molecular weight of Bromine is 79.904 g/mol, and 82.14 g/mol for cyclohexene.

(7.04 g Br) * (1 mol / 79.904 g) = 0.0881 moles Br

(4.75 mL) * (1 cm^3 / 1 mL) * (0.8111 g / cm^3) = 3.853 g cyclohexene

(3.853 g) * (1 mol / 82.14 g) = 0.0469 moles cyclohexene

It can be seen that since there are less moles of cyclohexene than of bromine, it is the limiting reagent.

Again, since it is a one-to-one ratio reaction, the number of moles is the same for all products and reactants. Thus, since only 0.0469 moles can be reacted, that is the maximum amount of product that can be obtained. Using the molecular weight of 1,2-dibromocyclohexane as 241.952 g/mol:

(0.0469 mol) * (241.952 g / mol) = 11.3486 grams of 1,2-dibromocyclohexane.