The aim of this experiment is to determine the concentration of a limewater solution by method of titration.

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To determine the concentration of a limewater solution.

Aim:  

The aim of this experiment is to determine the concentration of a limewater solution by method of titration.

  Ca(OH)2  (aq)    +   2HCl (aq)                        CaCl2 (aq)   +    2H2O (l)

The calculation below is to determine the dilution factor and the volume of HCl needed for this titration.

Moles of Ca(OH)2   =  Mass / Mr

1 / 40.1 + (16 x 2) + (1 x 2)

1 / 74

0.013513513 moles

Concentration of Ca(OH)2  =  N / V

  1. / 1

0.01 moldm -3

Moles  =  C x V

0.013513513 x (25/1000)

0.0003378moles

Ratio:

HCl       :     Ca(OH)2

2            :          1

0.000676 : 0.0003378

Moles of HCl = moles of Ca(OH)2  x 2

V = N / C

       0.00674 / 2

Volume of 2HCl = 0.000337 dm³ = 0.337cm3

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The volume of HCl is too small to titrate and therefore I will multiply the volume by x100.  To do this I need to divide the concentration of the acid by 100.  (2moldm-3 will be 0.02moldm-3)

Method of dilution:

Apparatus:

  • 5cm3 graduated pipette
  • 50cm³ burette
  • 250cm³ volumetric flask
  • funnel
  • burette stand
  • 250cm³ of limewater
  • Hydrochloric acid and concentration 2mol dm-3
  • 1g dm-3 of Calcium hydroxide (present in limewater)
  • 250cm3 conical flask
  • distilled water
  • 25cm3 pipette

To dilute the Hydrochloric ...

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