Question

Deterime the % of Acetic Acid in vinegar in your kitchen. Show how to determine it in words and make up random numbers to calculate it also.

Determine the purity of an Aluminum can. In words how would you determine the purity? Also, make up random numbers to calculate how to find the purity of an Aluminum can.

Identifiy the ions present in a sample possibly containing Ag+ Pb2+ Br2+ Na+ Ca2+. Construct a flowchart using these ions.

Answer 1

Determination of % of Acetic acid in Vinegar.

Take a portion (10 mL) of the vinegar solution into a volumetric flask and add a drop or two of phenolphthalein indicator to it. Titrate it with known comcentrations of NaOH solution (assume 1 M). When all the acetic acid reacts with the base, the solution turns pink. This is the end-point. Note the volume of NaOH used. Assume the volume of NaOH used is 25 mL.

Calculate the moles of NaOH consumed as follows:

Molarity = moles/volume

1 M = moles/10 mL

       = moles/0.025 L

moles = ( M)(0.025 L)

            = 0.025 mol

Since the acid is monoprotic, moles of NaOH = moles of acetic acid.

Moles of Acetic acid = 0.025 mol.

Mass of acetic acid = (0.025 mol)(60 g/mol)

                                = 1.5 g

Assume the mass of Vinegar solution to be 100 g.

% Acetic acid = mass of acetic acid/ 100 g vinegar *100

                      =   1.5 g/100 g *100

                      = 1.5%