Chemistry concentration of lime water.

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Introduction:

I am required to plan an experiment to find the concentration in g/dm³ of a 250Cm³ sample of limewater. This has been made such that it contains 1 g/dm³ of Calcium hydroxide.

Also available to me is Hydrochloric acid which has a concentration of 2.00mol/dm³. This concentration is too high therefore I am required to dilute it.

Limewater is formed by the reaction of Calcium Oxide with water this forms slaked lime, which is then dissolved with water.


Quicklime + Water                      Slaked lime

CaO(s) + H2O(l)                       Ca(OH)2(s)

It is necessary to react Hydrochloric acid with the Limewater so that the concentration of the Limewater can be established.

The reaction that takes place is:

Limewater + Hydrochloric acid                Calcium chloride + Water + Hydrogen

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

Apparatus:

The, equipment and chemicals that I will use are as follows: -
1) Pipette 25cm³
2) Volumetric flask 500cm³
3) Conical flask 250cm³
4) Burette
5) White tile
6) Clamp and stand
7) Indicator (methyl orange)
8) Limewater (250cm³ with 1g/dm³ of calcium hydroxide)
9) Hydrochloric acid- standard solution (conc. 2.00 mol/dm³)      10) Distilled water

 Method:

  1. Initially I am required to dilute the acid. The concentration I will dilute it to is 0.1 mol/dm³, which is a standard concentration for this titration, as it will give me a reliable result. Make up the 500Cm³ to dilute HCl acid from 2.00Cm³ to 0.1Cm³. Using the formula C1V1=C2V2.

C1V1=C2V2

2.00 x V1=0.1 x 500

V1=25Cm³

V1       :        V2

25       :      500

1:20

Therefore for dilute each 1Cm³ of 2 molar HCl with 20Cm³ of distilled water. To bring up to 500Cm³ you will need to poor 25Cm³ of HCl into a 500Cm³-graduated or volumetric flask, pour distilled water up to the graduation mark and shake the flask. This is the 0.1 molar HCl solution.

  1. Use a pipette to deliver 25.0Cm³ of the limewater into a clean conical flask.
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  1. Add a few drops of methyl orange indicator.

  1. Wash the burette with some of the acidic solution being used. Maker sure the solution runs into the tip of the burette.

  1. Once washed fill the burette up to the meniscus point at 0 point, this should be read at eye level.

  1. Arrange the Apparatus as below.

       

In order for the experiment to be accurate and reliable it will be necessary to dilute ...

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