Science Coursework Essays

Science Coursework Essays Science Coursework Essay Science Coursework Essay For my science coursework I have been asked to carry out an experiment to investigate the strengths of different sodium hydroxide solutions. By the end of my experiment I would like to find out which solution would be the best antacid to overcome indigestion. Indigestion is when acid from your stomach flows back up the oesophagus. I will be testing three sodium hydroxide (Na) solutions which have varying strengths, they are labelled A, B and C. To investigate the strength of each alkali I will use 4 different methods to measure the solutions.Phenolphthalein indicator is added to the antacid to turn it pink. Acid is added to the alkali solution to neutralise it. The amount of Acid which is added to each solution will determine the strength ness of it. Neutralisation is an irreversible chemical reaction; this is when an acid is neutralised by an alkali. This kind of chemical reaction produces reactants which are water and salt. The formula for this is: Acid + Alkali Salt + Water.The e quation for this experiment will be:Hydrochloric Acid + Sodium HydroxideHCl (aq) +NaOH (aq) NaCl (aq) +H2O (l)Apparatus:1 x 250cm3 Beaker,1 x 200cm3 Beaker,Pipette Filler,Pipette,Conical Flask,Clamp,Clamp stand,Test tube,Test tube stand,Burette,Measuring cylinder.Sodium Hydroxide solutions A, B and C,Hydrochloric Acid,Phenolphthalein (Indicator),Water.Strategy:In order to make this experiment fair I will be using 4 different methods to measure the acid used to neutralise the antacid solution. I will be using test tubes, beakers, measuring cylinders and the burette/pipette. I will test the equipment to see which method produces the most accurate results. By the end of the experiment I will be able to identify which method is the best and therefore conclude which equipment formed the most precise outcomes.Method 1 (Test Tubes)1. Pour one test tube full of the Sodium Hydroxide into a beaker.2. Add few drops of indicator to turn it pink.3. Add little amounts of HCl from the test tubes, into the solution and wait until it turned colourless.4. Record how many test tubes of HCl it took for the solution to be neutralised.Conclusion of this method:By using this method I found it difficult to record the results accurately. I was unable to control my hand when the acid was being added to the alkali. This made my result unreliable because the correct readings werent taken as the solution turned colourless. Therefore I will not be assessing this strategy as there are many defects and creates unreliable results.Method 2 (Beakers)1. Pour 100cm3 of Sodium Hydroxide in to the smaller beaker.2. Add few drops of indicator to turn pink.3. Use the larger beaker to add the acid to the alkali. Wait till the solution turns colourless.4. Record how much HCl was added to the Sodium Hydroxide.Conclusion of this method:I think this strategy was reasonably reliable as there was more acid in the beaker than the test tube, so I was able to stop as soon as the solution went colourless. Howe ver due to human error I dont think I got completely accurate results. Also as the graduations on the beaker were more spread out, me and my group couldnt tell exactly how much HCl was added to the Sodium Hydroxide. We estimated most of the results for this method. Overall I think this method is undependable as the results wont reflect the true outcomes of the experiment, therefore I will not be assessing this strategy.Method 3 (Measuring cylinders)1. Pour 100cm3 of Sodium Hydroxide into the measuring cylinder.2. Add few drops of indicator to turn pink3. Pour 100cm3 HCl into a measuring cylinder.4. Add HCl to Sodium Hydroxide until it turns colourless. Then record how much HCl was used and take it away from 100cm3Conclusion of this method:I think this method was very accurate because of the amount of graduations of the measuring cylinders. I was able to tell exactly how much acid was needed to neutralise the solutions. This slightly closed the gap for human error as the graduations were more reliable. However, it was difficult to pour acid from one cylinder to the other, sometimes a few drops of solution fell outside the measuring cylinder. This minor problem could affect the outcome of my results, therefore I will not be using this method.Method 4 (Burette Pipette)1. Pour acid into smaller beaker. Pour Sodium Hydroxide into larger beaker.2. Pour acid into the burette up to 0.003. Using the pipette and pipette filler pour 25cm3 of Sodium Hydroxide into a conical flask.4. Add few drops of indicator to turn pink5. Turn the tap of the burette to pour the Acid into the conical flask. Wait till the solution goes colourless.Conclusion of this method:Because of the amount of gradients on the burette, I believe that this is the best method. My results were extremely reliable and I was able to obtain accurate results. There was very little room for human error as the tap enabled me to stop the acid as soon as the solution went colourless. So, I have decided to use thi s method because of the amount of accuracy.Experiment:Method 4 is the overall method I will use as I consider it to be the best experiment to find out which Antacid is the strongest.Here is how to carry out the experiment, step by step:1. Collect all the equipment which is neededs of antacid brands include Rennie and Mucogel, and many of the popular antacid brands contain a mixture of more than one active ingredient. However some antacids can create some Side-effects such as diarrhoea and constipation. Also some antacids contain an ingredient called which forms a barrier that floats on the top the stomach contents to prevent reflux.Evaluation Conclusion:From my results and calculations I think my experiment went well. I did as much as I could to try and make the experiment fair and accurate however it was inevitable that a gap would be open for human errors. During my experiment my group always changed the person who was recording the amount of acid needed and the role of turning t he tap when the solution turned colourless. This may have affected our results as different people observe things in different ways. Someone may have turned the tap too early or too late which would affect the outcome of our results. Also to make my results more firm, I could have repeated the experiment a few more times in order to get a range of results.Human error makes way for things such as, not rinsing out glassware properly, misreading the burette and not detecting the end point accurately. There are other methods that I could have tried out as well such as a pH meter. A pH meter is an electronic instrument used to measure the pH (acidity or alkalinity) of a liquid. A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading. This would have given me more accurate readings.However I think titrations was the best strategy out of all the methods I had tried. It was extremely accurate and only little mistakes could be made. Although I did find a few outliers during my experiment. The biggest outlier I found was the first titration of the whole expermint which was a rough one, the result outcome was 24.30cm whereas the other results were between 25.00-26.00. This may be because the equipment werent cleaned put properly or the results werent read accurately. To make my results even more accurate I could have redone them, however with such a small difference I did not feel that it was not necessary. If I wanted to have strong results I could repeat these experiments where there would not be any outliers whatsoever.In conclusion, I think I chose the finest method to find out which antacid is the best solution to cure indigestion according to the equipment which was available. I tested other strategies and came to a conclusion that they werent accurate enough. Using a burette and pipette, secured my results and made them extremely reliable. My experiment was carried out carefully and precisely in order to get a fair result. Overall I believe my experiment was triumphant, and by the end of it I found out which antacid successfully combats indigestion.