Year 12 ATAR Chemistry - Titration experiment

ATAR Chemistry Unit 3


Practical Investigation - Titrations
Aim

The aim of this experiment is to determine the exact concentration of 0.1 mol L-1 HCl by titration
against the standard Na2CO2 solution.

Equipment (part 1)

anhydrous sodium carbonate (4g Na2CO3)
balance
volumetric flask (500 mL)
beaker (250 mL)
washbottle
storage bottle (500 mL)
distilled water
pipette

Equipment (part 2)

concentrated hydrochloric acid (6 ml HCl)
graduated cylinder (10 mL)
volumetric flask (500 mL)
storage bottle (500 mL)
beaker x2 (100 mL)
burette and stand
funnel
pipette (20 mL)
conical flask (250 mL)
standard Na2CO3 solution (refer to part 1)
methyl orange
distilled water

Diagram

, ATAR Chemistry Unit 3


Procedure

Refer to pages 49-53 of STAWA manual.

Calculations

n = cV
n = 0.05 x 0.5
n = 2.5 x 10-2 mol L-1

m = 2.5 x 10-2 x 106
m = 2.65 g

n=m/M
n = 2.
n = 2.547 x 10-2

c=n/V
c = 2.547 x 10-.5
c = 0.050943 mol L-1

0.5 – 0..50943 = 1.85% error

n = cV
n = 0.1 x 0.5
n = 5 x 10-2 mol L-1

V=n/c
V = 5 x 10-
V = 4 mL = 0.004 L

Reaction: Na2CO3 (aq) + 2HCl (aq) → 2NaCl (aq) + CO2 (g) + H2O (l)
CO32- (aq) + 2H+ (aq) → CO2 (g) + H2O (l)

Results

TRIAL 1 TRIAL 2 TRIAL 3

Volume of Na2CO3 25 mL 25 mL 25 mL

Initial HCl reading 2.5 mL 2.51 mL 2.4 mL

Final HCl reading 31.45 mL 30.4 mL 30.7 mL

Volume of HCl used 28.95 mL 27.89 mL 28.3 mL