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

The aim of this experiment is to determine as accurately as possible the concentration of a limewater solution

Extracts from this document...


Plan Aim The aim of this experiment is to determine as accurately as possible the concentration of a limewater solution. I have decided that in order for the experiment to work best, giving me an accurate as possible result, I will titrate the limewater with Hydrochloric Acid. I will ensure all necessary safety precautions are followed. The problem that may arise during this experiment is that there will be a different amount of Hydrochloric acid needed for each titration. This problem could arise because the limewater is sparingly soluble, meaning it has not completely dissolved. Therefore each 25 cm3 pipette of limewater will require different amounts of Hydrochloric acid. To help overcoming this problem I am going perform the titration experiment 5 times. From these results I will be able to calculate an average for the amount of Hydrochloric acid required to titrate 25cm3 limewater. The first thing I must do in this experiment is to calculate the concentration of Hydrochloric acid that can be used on a reasonable amount of limewater. I will than dilute the Hydrochloric acid given which is of 2.00mol dm-3 to that I have calculated. Following this I will be able to measure out the limewater ready for titration with the Hydrochloric acid. My chosen indicator is phenolphthalein because I believe it will give the clearest colour change, making it easily noticeable as to when the required amount of Hydrochloric acid to neutralise the limewater has be added. ...read more.


Method to Titrate hydrochloric acid and Limewater 2HCl(aq) + Ca(OH)2(aq) � CaCl2(aq) + 2H2O The safety precautions required for this experiment to be safe, is that I will require goggles to wear. The concentration of solution I am using is not that high, therefore there are not many dangers in using these solutions. I am going to find out the amount of 0.02 mol dm-3 Hydrochloric acid required to titrate 25cm3 of limewater. In order to do this I will accurately pipette 25cm3 of limewater. I will be provided with limewater in a large beaker, from this I can use a pipette to remove 25cm3, when drawing the limewater out I may overflow the 25cm3 mark. To remove a slight amount from the pipette, I will place my thumb over the top of the pipette and gentle wiggle it, this will let a minimal amount of air enter the pipette so that a slight amount of limewater is removed. To ensure the bottom the meniscus is level with the 25cm3 mark, I will keep the mark at my eye level. My thumb will tightly be kept over the top of the pipette when the pipette filler is removed. I will pipette the limewater 5 times, into separate conical flasks. I will stir the limewater solution before I take each 25cm3 aliquot to try to ensure as much calcium hydroxide has dissolved as possible. ...read more.


Calculations I am provided with 250cm3 1gdm-3 Ca(OH)2 This means I have 1g Ca(OH)2 in 1000cm-3 water We only want 250cm3 not 1000cm3 1000 250 = 4 Grams of Ca(OH)2= 1.00 4 = 0.25g We are going to use 25cm3 pipette of Ca(OH)2 Grams in 25cm3 = 0.025g Ca(OH)2 + 2HCl CaCl2 + 2H2 O 1 mole Ca(OH) 2 = mass = 0.025 Mr 74.1 = 0.000337moles Got 0.000337 moles Ca(OH)2 in 25cm3 1 Ca(OH)2 : 2 HCl 0.000337 : 0.000674 moles I am using 2.00 mol dm-3 HCl Volume = moles x 1000 Concn Volume = 0.000674 x 1000 = 0.337cm3 2.00 0.337cm3 : This volume of HCl is too small. I will be using a 50cm3 pipette, the accuracy will be too difficult to obtain. A reasonable volume will be between 20-35 cm3. In order to achieve a volume between 20-35 cm3 I will decrease the concentration. If 0.02mol dm -3 HCl is used: Volume = 0.000674 x 1000 = 33.7 cm3 0.02 This is a reasonable amount. Dilute HCl from 2.00 moldm-3 0.02 mol dm-3 In a 250 cm3 volumetric flask. 2 ? 0.02 = 100 This means 0.02 mol dm-3 HCl is 100 times weaker than 2.00 mol dm-3. 250cm3 ? 100 = 2.5cm3 Therefore I need 2.5 cm3 2.00 mol dm-3 HCl and dilute it to 250 cm3 with distilled water. A 10cm3 graduated burette will need to be used to get an accurate 2.5cm3 reading. ...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. Peer reviewed

    To determine the concentration of a limewater solution

    4 star(s)

    Then run exactly 2.5cm� of this into a 250cm� volumetric flasks. 4. Next add distilled water and make up 'to the mark'. 5. Then turn it up and down several times to ensure thorough mixing. 6. This dilution 2.5cm� into the volumetric flask will give me an acid which had a new concentration.

  2. How much Iron (II) in 100 grams of Spinach Oleracea?

    added to the Iron (II) Ammonium Sulphate (aq) had to be in excess to supply H+ ions I felt it would not be necessary to have an exact volume so I used a measuring cylinder to measure the quantity required instead of the more accurate equipment like a pipette which I used to measure out the volumes of the other solutions.

  1. To determine the concentration of limewater solution

    Empty out the flask into the beaker then wash out the flask. 4. Move 50cm3 of the new HCl solution from the beaker into the flask using the same method as in Step 1.

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

    Excess gastric acid in the stomach, acid indigestion, is typically neutralized by the ingestion of sodium bicarbonate (NaHCO3) or other neutralizing agent (antacids). Phenolphthalein phenophthalein structure Phenolphthalein is a sensitive pH indicator with the formula C20H14O4. Often used in titrations, it turns from colorless in acidic solutions to pink in

  1. Find the concentration of limewater solution Titration

    into the calcium hydroxide and the indicator will turn yellow/orange indicating it is an alkali. Put the conical flask on a white tile to help visability. Then measures the volume of liquid in the burette by placing a piece of paper behind the burette and reading the base of the meniscus and note it down.

  2. Determining the concentration of a limewater solution. This procedure will require a titration of ...

    When calculating an average I get: (34.6 + 34.5 + 34.45 + 34.5) ? 4 138.05 ? 4 = 34.5 (3s.f) HCl Number of moles = concentration (mol dm-3) x average volume (?). N = C x V N = 0.02 ?

  1. Antacid Experiment.

    area turned yellow, but as we stirred it the solution went back to purple again. As we got down to 8cm-cubed of hydrochloric acid used, the whole solution turned yellow and it took some time for it to change back to an alkali solution again.

  2. To determine the concentration of Limewater solution

    Methyl orange changes colour at pH 3.2 from red to yellow/orange. Screened methyl orange is a mixture of methyl orange and 'xylene cyanole' (a redox indicator). It changes colour at a pH of 3.8 from green to violet or reverse.

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