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

Analysis of vinegar. Comparing the concentration of different samples of vinegar.

Extracts from this document...


Unit 1.4a Aim: analysis of vinegar Introduction: quantitative analysis can be used to determine the concentration of active ingredient in foods. In this experiment, samples of vinegar has been analysed to calculate the concentration of standard vinegar to the restaurant and take-away vinegar. The restaurant and take-away should contain less acid than the standard vinegar. The take-away should water down the vinegar. Titration is used to find the concentration of an acid. Titration means how much acid is needed to neutralise an alkali. Titration is known to be the more accurate method to find the concentration of a solution. The burette is used to deliver the second reactant to the flask and the indicator is used to detect the endpoint of the reaction. When the dark pink colour changes to colourless indicate the reaction is complete. The indicator is important as both solutions are colourless so it will be hard to figure out when the reaction is complete. Titration always occurs between one base and one acid, the acid is the vinegar and the base is the sodium hydroxide solution. Ethanoic acid is produced when ethanol reacts with oxygen, it is a weak acid which can be happen anywhere where there is bacteria. The restaurant use Ethanoic acid (vinegar) for preservative and food flavouring. The Ethanoic acid's pH = 3. ...read more.


The precise volume was recorded to the nearest 0.05cm3. * The burette was placed on a clamp and stand as well as the 25 cm3 sodium hydroxide solution. * The tap of the burette was opened to titrate with the sodium hydroxide solution while mixing it. * As soon as the indicator turned to a colourless colour, the tap was closed. The remaining volume was recorded. * The volume was repeated and recorded three times with each sample. Results: Standard: Burette reading 1 2 3 Final reading 22.95 23.15 23.65 Initial reading 0.45 0.45 0.55 Volume used (cm3) 22.50 22.70 23.10 Average volume (cm3) 22.767 Restaurant: Burette reading 1 2 3 Final reading 31.25 30.95 29.95 Initial reading 0.35 0.55 0.45 Volume used (cm3) 30.90 30.40 29.50 Average volume (cm3) 30.267 Take-away: Burette reading 1 2 3 Final reading 42.75 42.15 41.85 Initial reading 0.45 0.45 0.25 Volume used (cm3) 42.30 41.70 41.60 Average volume (cm3) 41.867 Analysis: According to the table, the take-away units have bigger volume than the standard units which shows that more vinegar is added to the take-away to titrate. The volume used for restaurant is more than the standard but less than the take-away. The standard vinegar is more acidic than the take-away and the take-away is water down. On average 22.8 cm3 of standard vinegar required 25 cm3 of sodium hydroxide solution, 30.3 cm3 of restaurant vinegar required 25 cm3 of sodium hydroxide solution and 41.9 cm3 of take-away vinegar required 25 cm3 of sodium hydroxide solution. ...read more.


In addition, to make sure to close the tap in a way just to allow drops of the vinegar to go through. 2. Measurement error Measurement error can occur when people doesn't take the readings from the bottom of the meniscus which create parallax error. Another error can occur while taking the reading from the burette as the reading should be rounded up to the nearest �0.05 cm3 and the pipette should be �0.06 cm3. This can be accurate most of the time in experiment but sometime it can't be completely accurate. How to improve it? The best way to improve parallax error is to take the readings at the bottom of the meniscus and try to be more accurate rather than rounding up to the nearest numbers sometimes. During titration, the pH of the alkaline solution will decrease as more acid is added. When the pH goes down to 7, the solution will be neutral. If more acid is added, the pH will continue to go down and the solution becomes acidic. Only a few drops of sodium hydroxide are needed to neutralise the reaction. Ethanoic acid is a weak acid which means it does not fully dissociate into ions in water. To make the results more accurate, the experiment should be carried out more than 3 times. Personally, I am quite satisfied with my results as I find it accurate. ?? ?? ?? ?? Ahvashta Seeburrun 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Physical 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 AS and A Level Physical Chemistry essays

  1. Marked by a teacher

    Finding out how much acid there is in a solution

    It is not affected by heat and so if a substance like sodium carbonate was heated, it would evaporate any water present. Carbonates decompose on heating to give carbon dioxide and a metal oxide. In this case, Sodium Sulphate is produced with carbon dioxide and water.

  2. Drug: Antacid Effectiveness Analysis To determine the neutralizing ability of antacids in different ...

    of moles of HCl added to antacid: 0.0025 mol Results Table: Burette solution NaOH Indicator phenolphthalein Trial 1 2 3 Burette readings Initial 0.4 19.0 17.2 Final 19.0 39.0 38.1 Volume used (titre)/ cm3 18.6 20.0 20.9 Mean titre / cm3 20.5 No.

  1. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    o 4x 1000cm3 volumetric flask (�0.40cm3) o 5x 100cm3 volumetric flasks (�0.10cm3) o 8x 50cm3 burettes (�0.05cm3) o 1x 10cm3 pipette (�0.04cm3) o 1x 100cm3 pipette (�0.15cm3) o At least 5 beakers (50cm3 to 250cm3) o 1x 800cm3 beaker o 2x boiling tubes Other apparatus I will require: o Safety goggles o Balance (�0.01g)

  2. Investigating how concentration affects rate of reaction

    To do this I will test concentrations of 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.008 and 0.01mol/dm-3 of potassium bromide. I will then see how long each test took and decide how many of these trials I can do in the time I have available.

  1. Investigating the Volume of a Drop

    Put the Styrofoam cup containing the salt water into a second Styrofoam cup. 4. Take an eye dropper, fill the eye dropper with salt water 5. Take the graduated cylinder and position it so that the end of the eyedropper is 2cm from the bottom of the graduated cylinder.

  2. Methods of analysis and detection

    So how to Determine the % composition of a mixture by GLC: The area of a peak = 1/2 (Base � Height) Therefore, a chromatogram must show all the components and the detector are respond equally to all components. Green Tea Separation in GLC ?

  1. Run away exotherms

    2. The weighing machine The accuracy of measuring in mass scale: It is important to record the results up to at least 2 decimal places. It will have an effect on the accuracy of the final result. The Science Heat transfer: Heat transfers directly from the reacting substances to the water in which they are dissolved.

  2. Who’s Cheating on the Vinegar?

    o 50cm� burette o Funnel o 100ml conical flask o Two 75ml beakers o Clamp stand o Indicator (phenolphthalein) o Goggles Diagram Variables Independent: My independent variables are 5 different types of ethanoic acid labelled A, B, C, D and E.

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