Who’s Cheating on the Vinegar?

Who's Cheating on the Vinegar? Vinegar is an ethanoic acid. A wholesaler supplies chip shops. Design an investigation which identifies which chip shops are watering down the vinegar. Background Theory All acids contain the element "hydrogen". Water ionises the hydrogen to make it H+. To react all acids have to be ionised. Strong acids are almost completely ionised and weak acid are only partially ionised, which is why they don't react as much as strong acids. The pH of any acid would be below 7 (neutral), ranging from 1 (strong acid) to 6 (weak acid). Anything above 7 is an alkali, pH 14 being a strong alkali and pH 8 being a weak alkali. In titration we add alkali to the acid until the mixture neutralises. We use an indicator to tell us at which point the neutralisation occurs. When we have this information we can find the concentration of the acid using the calculation concentration = moles dm³ The acid we are using in this experiment is ethanoic acid (vinegar). It is a weak acid and is only partly ionised. This is an organic acid. In an ionised acid the following process has occurred: HCl --> H+ Cl- (using hydrochloric acid as an example) In this investigation we have taken 5 different acids, one being used by a chip shop (acid A), to test which one is the most concentrated and which one is the most dilute (watered down) by

  • Word count: 615
  • Level: AS and A Level
  • Subject: Science
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To investigate the effect of temperature on the rate of reaction

Title: To investigate the effect of temperature on the rate of reaction. Objective: To study on how temperature relates to the rate of reaction. Procedures: . 5cm3 of the hydrochloric acid is added to a boiling tube. 2. 20cm3 of the sodium thiosulphate solution is added to another boiling tube. 3. Draw a large cross on a piece of paper* and a beaker is placed over it. A heat-resistant mat is put under the paper. (*In the experiment, the heat-resistant mat is directly drawn with a cross, so that we did not need to draw it on a sheet of paper.) 4. Another beaker which contains water is prepared. 5. The two boiling tubes are put inside the beaker for a hot water bath, both with a thermometer*. In the first time of the experiment, this step is skipped because the experiment is done in room temperature, but a thermometer is still put into a boiling tube to measure the temperature. (*In the experiment, we have only got one thermometer so we measured the temperature of the water bath.) 6. After both of the solutions reach the suitable temperature, they are poured into the beaker which is prepared in step 3. Start the stop watch simultaneously. 7. The solution is stirred*. A person watches the cross vertically during the reaction. (*In the experiment, we did not stir the solution.) 8. Stop the stop-watch when the cross on the paper just 'disappeared'. 9. Record the time

  • Word count: 1018
  • Level: AS and A Level
  • Subject: Science
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