Vinegar :: essays research papers

Whos been cheating on the vinegar?Aim To investigate if the vinegars have been diluted by working start their concentrations.Scientific BackgroundVinegar is an acid and there fore can be neutralised by an alkali.Acid + Alkali common salt + waterHydrochloric acid + Sodium Hydroxide Sodium chloride + waterVinegar is a weak acid and therefore it only partially ionises in solution.CH3COOH CH3COO- + H+An alkali such as Sodium Hydroxide has a formula NaOH. If the alkali is strong then it ionises fully in solution.NaOH Na+ + OH-When the acid H+ reacts with the alkali OH- the solution neutralises.PredictionIf the acid has been diluted there will be less H+ ions present in the volume used. Therefore to scrape up the alkali more acid will be required. This is on the assumption that the alkali volume and concentration stay constant.MethodMeasure 10cm3 of 0.1m alkali into a measuring cylinder then place the solution into a 75cm3 conical flask.Then add 2-3 drops of indicator to the alkali (it will go purple in colour)Measure out 50 cm3 of the vinegar into a measuring cylinder and then place into a glass beaker.Then using a dropper add the vinegar drop wise to the alkali until 1-drop changes the solution to colourless.Replace the vinegar back into the measuring cylinder and record the volume of vinegar used. tell this process twice more, recording results.Then repeat the whole procedure for each different concentration of vinegar.Preliminary WorkAim- To find out which concentration of alkali will give accurate, measurable values.Concentration(M) Volume of acid(cm3)0.1m 21.45cm30.5m 78.9cm30.75m 100+cm31.0m 100+cm32.0m 100+cm3We decided from the results that the best measurable concentration of alkali would be the 0.1m concentrations.InvestigationTest 1Test 2Test 3AverageManufacturers10.27cm310.3cm39.73cm310.11cm3Shop 110.3cm39.5cm310.25cm310.11cm3Shop 218.4cm317.9cm318.4cm318.23cm3Shop 340.1cm338.45cm335.7cm338.08cm3 abridgment These results show that the vinegar fro m Shop 2 and Shop 3 have been significantly diluted with water or some other substance. The results obtained from shop1 show that its is truly similar in concentration to the manufacturers. Two of the results show that it is less concentrated than the manufacturers, but one shows that it is more concentrated, this is impossible so its is nigh likely collectible to human error and not taking the readings properly.ConcentrationsManufacturers= 110.11 = 0.0989119683Shop1 = 110.11 = 0.0989119683Shop2 = 118.23 = 0.054854635Shop3 = 138.08 = 0.026260504These results show an obvious difference in the concentration with the manufacturers being the most concentrated and shop 3s being the least concentrated.EvaluationThe results from this experiment can be considered reasonably accurate we took the results quite accurately.