Observation and Inference free essay sample

We have been provided with two samples of vinegar, one removed from a restaurant and one removed from a take-away. Trading Standards suspect these two establishments of watering down the vinegar. They need evidence that the samples contain less acid than the standard vinegar sample provided. What is the purpose of this? I’m a worker in the Trading Standards which carries out tests to see if restaurants and takeaways are watering down the vinegar. We will take one sample of vinegar from a restaurant and from a takeaway which we will carry out an experiment that will show us the results and concentration of the vinegar compared to the standard solution which Trading Standard provides. What is a Vinegar? Vinegar is a versatile liquid that is created from fermentation of ethanol, this is done by when yeast or any type of bacteria. These converts sugar in ethyl alcohol and carbon dioxide. We will write a custom essay sample on Observation and Inference or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Fermentation begins after the glucose enters the cell. The glucose is broken down into pyruvic acid and is converted into CO? , ethanol and energy for the cell. It also contains acetic acid, this acid is the key ingredient because of this acid, and you can taste the acidic taste in the vinegar. Vinegar also contains different types of acid like tartaric, and citric, typical vinegar has a pH of 2 – 3. 5. A standard table Vinegar contains about 4-8 percent of acid by volume Vinegar is mostly used for flavouring in food; by it also has medical, industrial and domestic use. What percentage of which acid should a standard, ‘table vinegar’ solution contain? A table Vinegar tends to be more diluted which can be 4/5% acetic acid and standard table Vinegar tends to be around 5% acetic acid (CH3COOH) which is also known as ethanoic acid. This is the chemical formula of acetic acid; ethanoic acid is diluted version of acetic. One molecule of acetic acid contains four hydrogen, two carbon and two oxygen atoms, this forms the chemical structure. Why is it important that vinegar contains the correct concentration of acid? It is very important that a vinegar contains the right concentration of acid, this is because if the company making the vinegar has a high concentration of acid in the vinegar it has a high potential of harm it can cause to the people would eat/drink this, they can seriously burn their inside which cause serious injury, or even enough to kill them, also if a vinegar is to diluted it would have no flavour therefore no one would taste the vinegar in the food. Trading Standards provides the information of the right concentration for companies would know what to do; this will avoid any problem, for example if they had the concentration of the acid to high, and it had injured a person. This is why there is a health and safety rules to be followed, for example the chemicals that they are using. must be disposed Trading Standard will perform an investigation and if the company was found guilty, there is a high chance that they will be fined, and if it was worse, the company has a chance of being shut down and put out of work. What is a Titration? A Titration is a technique where a solution of unknown concentration is identified by performing this test. A typical titration is where a titrant is added to a burette with the known amount of the unknown solution, until the reaction is complete. An acid-base titration is useful because acid-base titration techniques can help determine a pH of the chemical; also it allows us to see the lowest amount (in terms of volume) of a standardized substance you need to complete a reaction fully, which is why you add the substance slowly instead of quickly. Explain the general theory behind an ‘acid-base’ titration 1. Using a pipette, measure out exactly 25cm3 of sodium hydroxide 2. Add about 2-4 drops of the indicator phenolphthalein to the alkali 3. Fill the burette to the measurement marked 0cm3 with acid (Vinegar) 4. Turn the stock-cock on the burette to release the acid, wait until the alkali turns clear again. 5. Record the reading you have taken in a table. What type of indicator will be used and why? The indicator we are using is phenolphthalein, this is very good indicator this is because it is very easy to use, and it shows good results, it is also a safe chemical because even if it is dropped on the skin it would not irritate the person, when the reaction is occurring it turns the pink sodium hydroxide into the clear liquid it was before, this change will take place when the pH reaches about 10. Concentration Acid (0. 04) = Volume Alkali x Concentration Alkali (25 x 0. 1mmol/dm3) ? 51. 2cm3 On our experiment we have found out that two of the titration test I have examine prove that they are up to standard with Trading Standard, for example for sample A is the same results as the Trading Standard, but in sample B It has proven that there has been a watering down in the Vinegar, this means that this restaurant or Take away is watering down there Vinegar by 27. 24cm? I think the food establishment did this to save money on buying Vinegar, this means they will make more profit. the following calculation we use to identify the concentration of the Vol. acid X Conc. Acid = Vol. alkali X Conc. Alkali Burette unknown 25cm? Volume (by pipette) known value Evalution The results we have found turned out to be accurate to the Trading Standard results, for example sample A exactly got the same results as Trading Standard 23. 96cm? Sample B’s results show that they have water down the Vinegar compared to the Trading Standard, are results are very accurate this is why we received good results from the titration test, we may have done some mistake, out of the three experiment but not major mistake. There could have been an error made while we measured the Vinegar, are method was appropriate and our equipment’s were very accurate, this is shown by are accurate results which compares to the results of Trading Standard, we can improve this experiment by being more accurate with our measurement next time we perform this experiment.