Property tested
Equipment and technique used
Reason we chose this pH PH Meter, soaps and beakers.
How it was used: there were three different substances which were buffers, and these were used to test the pH meter and it would be calibrated during this to make sure it was the correct reading. The three soaps were then placed in the beakers, and tested using the pH meter after it had been calibrated.
We chose this test because it is an accurate test compared to the alternative test that could have been used. This was the universal indicator being placed in and seeing the colour change but the pH meter is more accurate when doing this test because this would tell the correct reading of the substance and give us quantitative data rather than rely on the human eye which can lead to human error. Also universal indicator doesn’t work with coloured soaps because they are already a distinct colour so it is much harder to see.
Conductivity
Ammeter, battery, electrode and the salt solution.
How it was used: the ammeter was connected to the battery and the electrode to make a circuit and then the electrode was placed in the salt solution. Then the ammeter would read the conductivity of the salt solutions.
This was used simply because it is more accurate than the other test which used a light bulb. This will not be accurate as you can’t really tell how conductive something is from the brightness of a light bulb. The ammeter was a good test because it was an accurate reading Which gave us quantitative results given in the units that were there, Amps.
Concentration of sodium hydroxide
Burette, pipette, phenolphthalein, and a filter funnel.
How it was used: the alkali would be measured out at approximately 250ml with the pipette which is a small plastic but accurate instrument to use and the phenolphthalein will be added to aid with spotting colour changes, instead of the Universal indicator because the universal indicator shows a range of colour but the Phenolphthalein shows just the couloir we need Then the acid will be put in the burette and it will be swirled and this will be added until it changes colour. This is a titration and this technique was used to find the concentration of the sodium hydroxide.
This was used simply because it is the easiest and efficient way to find out the concentration of a substance and the numbers that are on the burette will indicate to us the concentration needed on this because you just have to read how much acid has been used for the colour change and when there is a piece of white paper under it, it is easy to tell the colour change. A burette is useful because it shows un numbers (quantitative data) what amount of acid you used in your experiment and this is very useful for when writing up notes of what amounts of chemicals used.
Mass of exfoliating material
Buchner, microscope and balance.
How it was used:
The Buchner filter was used to filter all of the face scrub. We then used a microscope to view the face scrub at a micro level and we used a balance to weigh it. This was a very reliable thing to use as it was able to make sure that it was all filtered, weighed and viewed properly. The Buckner used for the filtering was a good choice because it sucked the water out of the solution and then it would be able to be weighed after it had dried out, and it can be used globally because it is very cost