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

Determining the concentration of a limewater solution by volumetric analysis

Extracts from this document...

Introduction

Determining the concentration of a limewater solution by volumetric analysis The best way to determine the concentration of a solution is by a titration, and as limewater (Ca(OH)2(aq)) is a base an acid/base titration would be most useful: Ca(OH)2(aq) + 2HCl(aq) 2H2O(l) + CaCl2(l) Precautions to take: working with chemicals, e.g. corrosive hydrochloric acid, means goggles should be worn as well as an apron to protect clothes and care must be taken in handling them, e.g. phenolphthalein is flammable. To get make accurate measurements of fluid bring to eyelevel and measure from the meniscus. To ensure that this test is fair there is only one dependent variable, the amount of titrant used. Using the same volumes of other chemicals throughout in an accurate way and keeping the surrounding conditions the same with a thermostat in the room also maintains a fair test as well as accurate results. The first thing to do is to dilute the hydrochloric acid titrant. ...read more.

Middle

burette * another 25cm3 pipette with filler to collect accurate and measured amounts of limewater for numerous titrations * limewater * and phenolphthalein to provide a visual indicator of the endpoint. I have chosen phenolphthalein as my indicator over methyl orange as the colour change is more prominent (turning from purple to colourless instead of yellow to red) but more importantly because the acid will be diluted and therefore weak and the pH of the final solution will be nearer to seven and this indicator has an end point closer to seven2 than methyl orange. Set up the burette to the stand and making sure the tap is closed, fill the burette to the 0.0cm3 mark. Do this using a funnel2 to prevent spillage but remember to remove this funnel afterwards as excess drips could ruin readings if left in the burette and ensure there is no air bubble at the tip of the burette1 that will make it seem there is more acid in the burette than there actually is. ...read more.

Conclusion

3.4 (overshot) 10.0 13.0 16.5 19.6 22.7 25.7 28.7 Titration(cm3) 3.4 - 3.1 3.0 3.5 3.1 3.0 3.0 3.0 Average titre = 3.1+3.0+3.1+3.0+3.0+3.0 =18.2 � 6 = 3.03cm3. If, on average, 25cm3 of Ca(OH)2(aq) required 3.03cm3 of HCl for the titration then the concentration of the limewater can be found with the formula concentration=moles�volume and the equation: Ca(OH)2(aq) + 2HCl(aq) 2H2O(l) + CaCl2(l) This equation shows that there is a molar ratio of 1:2 between Ca(OH)2 and HCl respectively. By working out the moles of HCl present the number of moles of Ca(OH)2 can be calculated and the formula can be completed: Moles of HCl = 0.20mol dm-3 � 0.00303dm3 = 6.06�10-4 The amount of moles of Ca(OH)2 is half the moles of HCl, so moles of Ca(OH)2= 6.06�10-4 � 2 = 3.03�10-4 moles. Concentration of Ca(OH)2 = moles � volume = 3.03�10-4mol� 0.025dm-3 = 0.01212mol dm-3 To change this in relation to grams per cubic decimetre simply times this by the molar mass of calcium hydroxide which is 74.08g mol-1 (Ca=40.08, O=16�2, H=1�2): Concentration of calcium hydroxide in the limewater = 0.01212 � 74.08 = 0.898g dm-3 (3.s.f.). ...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. How much Iron (II) in 100 grams of Spinach Oleracea?

    by 5. 0.000197 mol dm-3 x 5 = 0.000985 mol dm-3 Now that I know the mols of Iron (II) Ammonium Sulphate (aq) present in the titration I can work out the concentration of it. Moles = Concentration x Volume Concentration = Moles Volume Concentration = 0.000985 10 Concentration

  2. Find the concentration of limewater solution Titration

    Place the lid on the flask and, with one hand on the top and one on the bottom, turn the flask upside down. And turn it back upright again, allowing the air bubbles to travel to either end. Repeat this last procedure 3 times.

  1. determining the concentration of a limewater solution

    I will be diluting the hydrochloric acid to a 0.020 molar solution so that it is twice the strength of the limewater. I have explained the reasoning for this in my calculations. I want to obtain 300.00cm� of the dilute hydrochloric acid, at a ratio of HCl:H2O of 1:99.

  2. The Use of Volumetric Flask, Burette and Pipette in Determining the Concentration of NaOH ...

    In other words, a Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the OH- ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an electron-pair donor. The Lewis theory suggests that acids react with bases to share a pair

  1. The Use of Volumetric Flask, Burette and Pipette in Determining the Concentration of NaOH ...

    It can also be written in the form of a reaction including spectator ions. For example, when an HCl solution is mixed with an NaOH solution, the reaction, with spectator ions, would be i.e., acid + base water + salt.

  2. Determine the concentration of a limewater solution.

    Several possible indicators should be listed, as at this stage we are unsure as to which indicators will be available when we carry out the experiment. Any indicators we use will have to be suitable for a strong acid and a weak base titration, this can be decided by checking

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

    The acid and alkali have neutralized each other. * Now start your second titration, but this time make sure that you add the acid solution drop by drop, to get your sodium carbonate solution to become clear. * Make sure that you control the flow of acid solution so that too much does not flow into the beaker.

  2. Determining the concentration of a limewater solution.

    The general equation for a neutralisation reaction is: Acid + Metal Hydroxide Metal Salt + Water The word equation for this particular reaction is: Limewater + Hydrochloric Acid Calcium Chloride + Water + Hydrogen The balanced symbol equation for this particular reaction is: Ca(OH)2 (aq) + 2HCl (aq) CaCl2 (aq)

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