Slaters Project

In order to find the pH of each household item by using pH paper, the pH paper was placed on the drop plate. Using the dropper, start by having the household item dropped onto the pH paper. Immediately observe in order to spot any colour changes on the pH paper. To determine the pH by using the pH scale and record the pH on your table of observations. Depending on what the pH is, it could be very acidic, basic or neutral. Repeat these steps for the other products.

7 Corvettes These are used instead of test tubes as corvettes are required if a colorimeter is to be used. One corvette is needed for each pH and one for the control. These can then be reused for the repeats. Syringe calibrated at 0.1 cm³ intervals

pH was recorded every time 1.00 mL of NaOH was added to beaker. When the amount of NaOH added to the beaker was about 5.00 mL away from the expected end point, NaOH was added very slowly. Approximately 0.20 mL of NaOH was added until the pH made a jump. The pH was recorded until it reached ~12. This was repeated two more times. The pKa of each trial are determined using the graphs made on excel.

In 2 and 7 I added 50 mL of .1 M NaCl. I added sodium acetate to the rest of the beakers: 1 gram to 3 and 8, 5 grams to 4 and 9, and 10 grams to 5 and 10. I then filled the beakers that contained the solid sodium acetate with 50 ml of .10 M acetic acid. Specifics can be found on page 84 of the lab manual. Though the lab manual instructed to use a pipet, we did not have an accurate 1 mL pipet or a graduated pipet, so we instead prepared two graduated burets with 1 M Sodium Hydroxide and 1 M hydrochloric acid. Using a standardized pH probe with a Lab Pro to measure changes in pH, we added 1 mL of HCl at a time and recorded the changes. The same was done for the NaOH.

mL cylinder to the beaker on the stir plate and empty it into the beaker. Place the pH probe in the beaker and record the pH in the data table. Drag the beaker to the red disposal bucket. Double-click the bottle of NaHCO3 to move it to the Stockroom counter. Repeat steps 5 and 6 for KNO3.

Measure 500ml of tap water in the 500cm3 beaker, then measure 5g of sodium hydrogen carbonate using the 50cm3 beaker and weight scale and place in the beaker of water, using the glass rod to dissolve it into the mixture.

7. Using the slider on the right hand side, add NaOH to the HCl in the Erlenmeyer flask (This action is known as titrate). Add the indicator until the color of the indicator turns a light shade of pink.

To make the buffer solution you need 0.2 mol dm-3 of Na2HPO4 and 0.1mol dm-3 of citric acid this will give 100cm3 of buffer. Here is how to get the different pH in the buffer solutions:

4.Measure 35mL of warm water and add them into each of the 4 test tubes at about roughly the same time. It is essential that the water is warm. Do not seal the test tube.

To begin, three sets ofabout 0.3000g of KHP are weighed out on an analytical balance. Put the three sets of KHP into three separate, labeled flasks. All three sets of the KHP is then dissolved with approximately 50mL of deionized water. Next, a buret is used to start the actual titration. Buret is initially filled to 0.00mL mark with the NaOH solution, this is recorded as initial volume. Next, add 2-3 drops of phenolphthalein indicator into each of the three flasks containing KHP. A magnetic stir bar is then added to the first flask, and placed above a stir plate. Everything is positioned under the buret. Stirrer is put on medium speed and the titration can start. Slowly release the NaOH into the KHP flask. As the end point is reached, a pink color will be seen in the flask. When the lightest pink possible remains in the solution for more than 30 seconds titration is complete. The final volume is recorded, and the same steps are taken for the other two sets of KHP solution. Finally, blank titration is completed to determine deviation.

1 ml of water should be added to the first test tube and make a note. In the second test tube, 1 ml of methyl alcohol should be added. In the third test tube, 1 ml of hexane must be added. Lastly, the fourth test tube will be a control.

A total of 1.5 mL was added to produce a pH of around 6. The mixture was stirred for an additional 30 minutes.

I also learned that pH scale is measured either with litmus paper, you dip in the substance and measure that color to a acidity color

An alternative hypothesis was them formed which was that the woodlouse would prefer to migrate to the 0.9% NaCl solution rather than the 10% solution. This was stated because the woodlouse live in a moist environment thus meaning the water is fresh water rather than containing much salt. After the results were calculated, the null hypothesis was rejected because the woodlouse favored the solution with the least amount of salt (NaCl) which was the 0.9% side. This proved that the woodlouse preferred a more fresh water environment. A question was then raised as to why some of the woodlouse still decided to travel to the 10% NaCl water? This experiment could have been more improved if the choice chamber contained the woodlouse’s natural habitat which would to be to insert grass and dirt into the choice chamber. This would have improved the experiment because it allows the woodlouse to recognize a familiar environment rather than just travelling to a piece of paper with different concentration of NaCl water on

From this experiment, I have concluded that my hypothesis is neither right nor wrong. This was shown as the slaters did not enjoy too much moisture (for example the 100mls) where slater numbers in those areas was very limited or in particularly small amounts. They also did not enjoy the very dry soil as numbers in that area was also