Question

A commercial vinegar is analyzed for the percent acetic acid present. The data for Trial 1 is listed in the table below. Complete the table to determine the percent. (See Report Sheet) Record calculated values with the correct number of significant figures. Preparation of Vinegar Sample Analysis of Vinegar Sample

Answer 1

3)

Volume of NaOH used = final buret reading - initial reading

volume of NaOH used = 25.4 - 3.7

volume of NaOH = 21.7

5)

we know that

moles = molarity x volume (ml) / 1000

so

moles of NaOH = 0.0940 x 21.7 /1000

moles of NaOH = 2.0398 x 10-3

6)

NaOH is added to neutralize CH3COOH and the reaction is

CH3COOH + NaOH ---> CH3COONa + H20

from the reaction it is clear that

moles of CH3COOH = moles of NaOH added

so

moles of CH3COOH = 2.0398 x 10-3

7)

we know that

mass = moles x molar mass

molar mass of CH3COOH = 60 g

mass of CH3COOH = 2.0398 x 10-3 x 60

mass of CH3COOH = 0.122388 g

8)

percent mass = ( mass of CH3COOH / mass of vinegar ) x 100

percent mass = ( 0.122388 / 3.06 ) x 100

percent mass = 4

so percent mass of CH3COOH is 4%