Determination of the % by volume of ethanoic acid in 100cm^3 of water

by jallo19795 (student)

I.B. CHEMISTRY: PRACTICAL 08-12-12.

P2,P3,& P4-STOICHIOMETRY

SULAIMAN JALLOH

AIM: 1) To prepare a standard solution of potassium hydrogen phthalate by weighing and dissolving it water of correct volume.

2)To use the standard solution of 1) to standardize(find the concentration of) sodium hydroxide solution.

3)To determine the percentage of ethanoic acid,by volume,in vinegar,by titrating with standardized sodium hydroxide in 2)

1) MAKING A STANDARD SOLUTION OF POTASSIUM HYDROGEN PHTHALATE

RAW DATA TABLE

The purity of the acid is given as 99.5+/-0.5%

Calculations for the mass of the acid needed to make 250

of solution of the acid.

Equation for the reaction:

C6H5COOKCOOH+NaOH

C6H5COOKCOONa+H2O

so,the mole ratio of the acid to base is 1:1

This means 1 mole of acid gives 1 mole of the base.

number of moles of sodium hydroxide,Nb=c

v

where c=concentration of sodium hydroxide

v=volume of solution titrated

Nb=0.1

250/1000)

Nb=0.0250moles

Hence the number of moles of the acid will be 0.0250 moles since the mole ratio is 1:1

number of moles of acid,Na=mass of the acid/molar mass of the acid

mass of the acid,Ma=molar mass of the acid

number of moles of the acid

molar mass of the acid:

Mr(C6H5COOKCOOH)=6(12.01)+5(1.01)+12.01+2(16.00)+39.10+12.01+2(16.00)
+1.01

=205.24

Hence,the mass of the acid,Ma=0.0250

205.24

=5.131g to 3 decimal places

Results Table:

Concentration of the acid,Ca=number of moles of the acid/volume of the acid

=0.0250

1000/250.00

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