Question

Please help with calculating the yield on this first page...the other two are data for your calculations. I believe the limiting agent is 2-methoxyphenol, but I don't know how to calculate the percent yield, or how to set that up...thank you

Answer 1

For

2 methoxy phenol

molecular weight M =124.14 g/mol

volume taken =1ml

density =1.11g/ cm³ or 1.11 g/ml

1cm³ =1ml

we know density = mass/volume

or mass=density *volume

mass = 1.11 g/ml *1ml =1.11 gm

moles =mass taken /molecular weight

moles n= 1.11 gm/124. 14g/mol=8.94 *10^-3 moles

for

sodium hydroxide

molecular weight M=39.99 g/mol

volume taken =2ml

Molarity =6.25 M

molarity =

6.25 M

molarity = number of moles/volume of solution in L

by definition of molarity we can say

1L=1000 ml of 6.25 M of sodium hydroxide contain =6.25 mole of NaOH

1 ml of 6.25 M of sodium hydroxide contain =6.25/1000 mole of NaOH

2 ml of 6.25 M of sodium hydroxide contain =(6.25/1000) *2mole of NaOH

2 ml of 6.25 M of sodium hydroxide contain =0.0125 mole of NaOH

for 3 chloro 1,2-propanediol

molecular weight M=110.54 g/mol

volume taken =2ml

Molarity =5.98 M

molarity = number of moles

volume of solution in L

by definition of molarity we can say

1L=1000 ml of 5.98 M of 3 chloro 1,2-propanediol contain =5.98 mole of 3 chloro 1,2-propanediol

1 ml of 5.98 M of 3 chloro 1,2-propanediol contain =5.98/1000 mole of 3 chloro 1,2-propanediol

1.8 m of 5.98 M of 3 chloro 1,2-propanediol contain =(5.98/1000) *1.8 mole of 3 chloro 1,2-propanediol

1.8 ml of 5.98 M of 3 chloro 1,2-propanediol contain =0.010764 mole of 3 chloro 1,2-propanediol

From the number of moles we see 2-methoxyphenol is present in lesser amount so it is limiting reagent

1mole of 2-methoxyphenol react with 1 mole of 3-chloro 1,2-propanediol to produce 1mole of guaifenesin

0.00894 mole of 2-methoxyphenol produces 0.00894 moles of guaifenesin

Molecular weight of guaifenesin is 198.2 g

1mole of any substance=molecular weight

So 1 mole of guaifenesin weighs 198.2

0.00894 moles of guaifenesin weighs=198.2*0.00894=1.7 7gm

Theoretical yield = 1.77gm

actual yield=0.329gm

Percentage yield=actual yield*100/theoretical yield

℅ yield=0.329 g*100/1.771g

℅yield =18.58℅