How to prepare a standard solutionFirst off we need to decide what type of standard solution we want to make. I have chosen Sodium Hydroxide (NaOH) as it was used in a recent practical based around Titration.
First off we need to work out the total mass in NaOH. To do this we look at the atomic mass of each individual element in NaOH.Na=23O=16H=1Then we add these values up to give us an overall mass of 40. This means we need to dissolve 40g of Sodium Hydroxide in 1 litre of water.
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This will give us 1 mole of NaOH solution.Steps to prepare solutionFirst weigh out 40g of NaOH, make sure it is accurate otherwise too much or to little will damage results.Next add this mass to some distilled water. It needs to be distilled so no other elements are present in the experiment.
Mix the solution together, preferably with a glass rod.After that transfer this liquid solution to a flask and top it up with more distilled water in order to make it reach 1 litre.If you wanted 0.1 moles you simply would divide your 40g by 10 to get 4g. You divide by 10 because 1 mole divided by 10 is 0.1 moles.Similarly if you wanted 2 moles you would multiply your 40g by 2 to get 80g.
You multiply by 2 because 1 mole x 2 = 2 moles.Full report for Sodium Hydroxide and Hydrochloric AcidAim:The aim of the experiment is to work out how much of an acid is required to neutralise an alkaline. We have HCL which is an acid and NaOH which is an alkaline.Prediction:I predict that when that when the volume of Hydrochloric Acid reacts with the same volume of Sodium Hydroxide it will neutralise the substance.Hypothesis:I believe it will be once the same volume is added because if it wasn’t the exact same volume then the substance as a whole might not be at 7. Once it does this I feel it will make water.
Equipment:BurettePipetteClamp standFunnelpH indicatorBeakerConical FlaskSubstances:Hydrochloric AcidSodium HydroxidePhenolphthalein indicatorRisks and Hazards:Hydrochloric Acid is corrosive, therefore it can damage skin and is very harmful if it gets in your eyes.Sodium Hydroxide is also corrosive so make sure it doesn’t enter eyes. (wear safety goggles)Glass from equipment can cut skin if it breaks so take care when carrying them.If indicator enters mouth and is swallowed it can harm stomach.
Method:Place the burette in the clamp stand and make sure the tip is closed.Then place a funnel at the top and begin to pour hydrochloric acid down the burette until it reaches the zero mark.Place a beaker under the burette and check there are no air bubbles in the tip of the burette.
If there are open the tap until they disappear and add the substance in the beaker back into the Burette.Next use a pipette to add 25.0cm³ sodium hydroxide into a conical flask.Then add two drops of Phenolphthalein indicator into the conical flask.Begin to titrate in the sodium hydroxide 1cm³ at a time after placing the flask below the burette.Once it has changed colour to clear record the volume used to work out the volume required.
Repeat this process after washing the flask out in order to gain more results and improve accuracy. Aim for about 4 or 5 tests.Finally work out the average amount of HCL used across each test to see how is required to neutralise the alkaline.Results:TitrationBurette Readings (cm³)Volume of HCL RequiredInitial FinalTrial2 222010 191920 212130 2020Results Discussion:These results show us that we started at the 0 point on the burette and as we moved down while releasing HCL we can see how much was required each time. Our results can be used to work out the average by adding the volume required in each trial and dividing it by the number of trials. 19+21+20=6060/3=20This means it takes 20.0cm³ of hydrochloric acid to neutralise our 25.0cm³ of sodium hydroxide.
Conclusion:The purpose of this task was to see how much of an acid is needed to neutralise an alkaline. I originally thought it would have to be the same volume as each other however it turns out it doesn’t. Rather than 25cm³ of hydrochloric acid reacting with 25cm³ of sodium hydroxide, it only needed 20cm³ of hydrochloric acid to react with the 25cm³ of sodium hydroxide.Evaluation:Overall I feel our experiment went very well. Each of our results was within 1cm³ of the average so we must have been doing it right. We were well organised and communicated well. The only downfall of our experiment was in the trial attempt we didn’t put the HCL back in the burette when releasing the air bubbles hence why it is at initial volume of 2 in the chart.
However that is what the trial attempt is for so we knew what exactly to do in the main attempts which all started at 0.