• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Determination of the concentration of lime water solution

Extracts from this document...


Victioria Nicholls Chemistry Coursework Title: Determination of the concentration of lime water solution Objective: The aim of this experiment is to determine the concentration of an unknown limewater solution in g dm-3 as accurately as possible, which contains 1g dm-3 of calcium hydroxide. This will be done by titration with hydrochloric acid. The Reaction occurring is: Ca(OH)2(l) + 2HCl(l) � CaCl2(l) + H2O(l) Apparatus: Metal stand Burette Conical flask 25cm3 Pipette 250cm3 volumetric flask Lime-water solution Hydrochloric acid Methyl-red indicator Diagram Method: 1.Firstly, determination of the concentration of hydrochloric acid to be used is to be carried out, as the 2.00 mol dm-3 solution of hydrochloric acid supplied is too concentrated. This was done by diluting the 2.00 mol dm-3 solution with water to the values 1.00, 0.50, 0.10 and 0.02mol dm-3 of hydrochloric acid. The was done using preliminary results: Concentration of HCl (mol dm-3) Volume of HCl required to neutralise the lime water (cm3) ...read more.


This is when the solution becomes neutral i.e. pH7. (See method on how to titrate accurately - see appendix 2) 7. So after finding a suitable dilution of hydrochloric acid to use which was 0.02 mol dm3, the burette was filled with 50cm3 of hydrochloric acid, using a measuring cylinder that measures to 1cm3. We had to make sure that there were no air bubbles present in the burette jet, this would have affected the volume of liquid in this method. To avoid this we kept the burette jet running until we could see clear that there were no air bubbles present in the burette to affect the accuracy of our results. 8. We needed an indicator which has an end point is below pH 7 because there is a sharp change below pH7 and a gradual change above pH 7. We needed a sharp change. The colours, ranges and end points vary considerably as can be seen in the table below: Name of dye Colour at low pH pH range End point (Pkind) ...read more.


Results Titration Start (cm3) Finish (cm3) Volume (cm3) Rough 50 19.0 31.00 1 50 19.3 30.70 2 50 19.4 30.60 3 50 19.5 30.50 Average Volume = 30.60cm3 Number of moles of HCl used = volume � concentration 1000 = 30.60 � 0.02 1000 = 0.0006mol dm-3 The reaction occurring is: Ca(OH)2 + 2HCl � CaCl2 + H2O As 2 : 1 HCl Ca(OH)2 0.0006 = 0.0003 moles of Ca(OH)2 2 0.0003 moles in 25cm3 0.0003 � 40 = 0.012 moles ArCa(OH)2 = 74 Moles = Mass � Mass = Moles � Ar Ar = 0.012 � 74 = 0.1g/dm-3 Therefore, the concentration of limewater is 0.1g/dm-3 Safety Substance Risk Precaution - Hydrochloric Acid - CORROSIVE - Can cause severe burns. Can be very dangerous to eyes and skin. Solutions equal to over 0.5m should be labelled corrosive. Those over 0.5m should be relabelled irritant. - Wear gloves and goggles at all times Instructions to follow before starting experiment: - Move all obstructions e.g. stools and bags - Clear work area of unnecessary equipment - Beware of spillage's - Take care with glass equipment - if breakage occurs report immediately ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. The Determination of an Equilibrium Constant.

    H2O = 18 g/mol Number of moles of H2O = 100 / 18 = 5.556 mole 2 Volume of NaOH used in titration is 33.55 cm3 Number of moles of OH- used = 0.2 / 1000 * 33.55 = 6.7 * 10-3 mole ?1 mole of H+ react with I

  2. Finding out how much acid there is in a solution.

    All the other results obtained in my actual experiment were all accurate. Percentage error - Percentage error = Error x 100 Of Na2CO3 = Reading = 0.005 x 100 2.65 = 0.19% 0.19% - This is the percentage error reading of sodium carbonate powder that was measured on the digital scale.

  1. Chemistry concentration of lime water.

    The Limewater used will be a relatively weak base so it will be appropriate to use methyl orange as it has an end point on the ph scale between 8-5. Whereas phenolphthalein indicator has an end point much higher up in the ph scale.

  2. Determining the concentration of lime water

    * I will then add the deionised water which will be provided to the volumetric flask until it reaches the marked line on the volumetric flask. I will then shake the flask additionally in order to make sure that the Nitric acid has been diluted with the deionise water.

  1. determining the concentration of a limewater solution

    When doing the other titrations I had to make sure that as soon as the phenolphthalein started to go clear I added the dilute hydrochloric acid drop by drop to ensure that I was not using too much, which would allow me to get the best result when calculating the exact concentration of the limewater solution.

  2. To determine the concentration of a lime water solution

    First of all dilute the hydrochloric acid using by adding slowly 25ml of 2.00moldm-3 HCl to 475ml of de-ionised water in the 500ml beaker 4. Then, using a pipette, put 100ml of the HCl solution into the burette 5. Put 50ml of limewater into a conical flask using the pipette

  1. To determine the concentration of lime water

    in g dm?3: Formula mass (Ca(OH)2)= 40.1+(16+1)*2 = 74.1g Concentration of Ca(OH)2= 74.1* 1.13*10?2 g dm?3 = 0.83733 g dm?3 = 0.84 g dm?3? I conclude that my results are quite accurate as they are near to the 1g dm?3 estimate given to us.

  2. Determine the concentration of lime water.

    After this it the results must be noted in a table as I have indicated in the table below. Titration 1 Titration 2 Titration 3 Final Reading 6.70 cm3 12.30 cm3 17.90 cm3 Initial Reading 1.00 cm3 6.70 cm3 12.30 cm3 Titre 5.70 cm3 5.60 cm3 5.60 cm3 Average titre

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work