Question

For the reaction,`2x`+`3y`+`4z``rarr``5w` Initially if 1 mole of `x`,3 mole of `y` and 4 mole of `z` is taken and 1.25 mole of `w` is obtained then what is the % yield of this reaction?

Answer 1

The percent yield is 50 %.

Explanation:

This is a limiting reactant problem.

We know that we will need a balanced equation and moles of each reactant.

1. Gather all the information in one place with the experimental number of moles below the formulas.

`color(white)(mmmmmm)2x + 3y + 4z = 5w`
`"Amt/mol:"color(white)(ml)1color(white)(mm)3"color(white)(mm)4`
`"Divide by:"color(white)(ml)2color(white)(mm)3color(white)(mm)4`
`"Moles rxn:"color(white)(m)0.5color(white)(ml)1color(white)(mm)1`

2. Identify the limiting reactant

An easy way to identify the limiting reactant is to calculate the "moles of reaction" each will give:

You divide the moles of each reactant by its corresponding coefficient in the balanced equation.

I did that for you in the table above.

`x` is the limiting reactant because it gives the fewest moles of reaction.

3. Calculate the theoretical yield of `w`

`"Theoretical yield" = 1 color(red)(cancel(color(black)("mol"color(white)(l) x))) × ("5 mol " w)/(2 color(red)(cancel(color(black)("mol "x)))) = "2.5 mol"color(white)(l)w`

4. Calculate the percent yield

`"Percent yield" = "Actual yield"/"Theoretical yield" × 100 % = (1.25 color(red)(cancel(color(black)("mol"))))/(2.5 color(red)(cancel(color(black)("mol")))) × 100 % = 50 %`