Question

5.0mL of cyclopentadiene and 15mL of 4 M maleic anhydride solution in 1,2-dichloroethane (maleic acid) were mixed. The product weighed 1.34 grams. What is the theoretical yield?

Answer 1

The theoretical yield of product is 9.8 g.

Explanation:

We must first identify the limiting reactant, and then we calculate the theoretical yield.

We start with the balanced equation.

`"cyclopentadiene + maleic anhydride" → "DA adduct"`

`color(white)(mmmmmmmm)"Cp" + "MA" → "adduct"`
`"MM/g·mol"^(-1): 66.10color(white)(ll) 98.06color(white)(mll) 164.16`

(a) Identify the limiting reactant

We calculate the amount of adduct that can form from each reactant.

Calculate moles of `"Cp"`

The density of `"Cp"` is 0.786 g/mL.

`"Mass of Cp" = 5.0 color(red)(cancel(color(black)("mL Cp"))) × "0.786 g Cp"/(1 color(red)(cancel(color(black)("mL Cp")))) = "3.93 g Cp"`

`"moles of Cp" = 3.93 color(red)(cancel(color(black)("g Cp"))) × "1 mol Cp"/(66.10 color(red)(cancel(color(black)("g Cp")))) = "0.060 mol Cp"`

Calculate moles of `"adduct"` formed from the `"Cp"`

`0.060color(red)(cancel(color(black)("mol Cp"))) × "1 mol adduct"/(1 color(red)(cancel(color(black)("mol Cp")))) = "0.060 mol Cp"`

Calculate the moles of `"DA"`

`"Moles of DA" = 0.015 color(red)(cancel(color(black)("L MA"))) × "4 mol DA"/(1 color(red)(cancel(color(black)("L DA")))) = "0.06 mol DA"`

Calculate moles of `"adduct"` formed from the `"DA"`

`0.06 color(red)(cancel(color(black)("mol DA"))) × "1 mol adduct"/(1 color(red)(cancel(color(black)("mol DA")))) = "0.06 mol adduct"`

This is an equimolar reaction of `"Cp"` and `"DA"`.

There is no limiting reactant.

(b) Calculate the theoretical yield of `"adduct"`.

We can use either reactant to calculate the theoretical yield

`"Theoretical yield" = 0.060 color(red)(cancel(color(black)("mol adduct"))) × "164.16 g adduct"/(1 color(red)(cancel(color(black)("mol adduct")))) = "9.8 g adduct"`

The theoretical yield of product is 9.8 g.