Griffin
Dr. Burrell
Bio-111-900
April 10, 2016 Determining pH
Introduction:
In this Lab report we will be using Red Cabbage extract as an indicator to determine the pH of substances. The purpose of this experiment is to see if and how base and acids react. Indicators are chemicals that change color depending on the pH solution that they are dissolved in. This experiment will determine which items we use to determine ph. The pH of a solution indicates its acidity or alkalinity. There is a ph. scale that determines if the items such as lemons or bleach are an acid or a base. I have chosen to use red cabbage in this experiment so that I can know the range of the item that
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Buffer solutions needed are in test tubes. Then get seven test tubes and place them in a rack and label them. Place 3 ml of buffer into the (test tube 1 should be put in 1). I then put the appreciate amount in I each tube. Then added 1.5 mL of red cabbage juice to each tube. Then I covered the tubes with Para film and mixed thoroughly and waited until I saw changes if there were any.
Results:
The results of my experiment were as follows the pH of 2 has a pink color and the ph. of 12 had a blue color. As I go down the chart the pH turned darker as I got to 6 and higher. See the figure 1 for the changes in the color as you go from a pH of 2 to 12. As I got to 10 it was still a green blue color.
Figure 1
Discussion:
I have found out that the any number below 7 is more acidic such as lemons and bananas. I have found that in conducting this experiment that cabbage juice was more acidic when added to the Ph. of 6 or less within the buffer solution. Greater with the more Alkaline. There is more acid which makes the solution a red to pink color and then it goes to neutral then it go to green than to blue as the level gets
Purpose/Hypothesis: The purpose of this experiment is to use both cabbage juice and pH paper to determine the pH of household items. This way, we can tell which products are basic and which one are acidic. If we use cabbage juice as an universal pH indicator by comparing it to pH paper then pH determined by the cabbage juice will be unstable because by using cabbage juice, it can be different depending on how diluted it is.
The red cabbage indicator shows how a usual household product such as red cabbage can make a suitable indicator and be able find out if a chemical is either and acid, alkali or neutral. Acids are a chemical that reacts with an alkali neutralising it producing water and a salt. Acids are also commonly found to be sour tasting. Acids react with metals, releasing hydrogen gas and leaving behind a salt they also can conduct electricity. Acids also readily give off hydrogen ions and have a pH level lower than 7. Some more common laboratory acids are Hydrochloric, Sulphuric and Nitric Acids. Sulphuric acids and water are used in car batteries as the electrolyte.
Add to this 5 drops of pH 4 buffer solution * Measure out 2 cm³ starch solution * Start stopclock and leave for 1 minute * Measure out 1 cm³ amylase and place in second corvette * Add to this 2 cm³ distilled water *
twice. Place the pH probe in the beaker and record the pH in the data table. Drag the beaker to the red
To improve the results from the experiment buffer solutions that were not whole pHs could have been used e.g. pH 4.5, 5.5 etc. This would have provided more reliable results as a wider range of results would have been produced. Using pHs with decimals would also help to more accurately determine the optimum pH as the optimum may have been above or below the pH stated in the hypothesis; 8. In this experiment however the optimum is taken at 8 because the graph does not rise again.
Table 2: Consists of color extract taken from a red cabbage for a natural indicator. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic.
Measure and add 5cm3 of buffer solution using a measuring cylinder with the pH 3 into a test tube using a pipette and place the potato cylinders into the test tube.
Red Cabbage pH Mark Lab Work The Goal of the investigation was to look for and understand the different chemicals (Acids, alkalis and neutral) work and see a change in color. Introduction: The red cabbage mark shows how simple household product such as red cabbage can make a suitable mark and be able find out if a chemical is either an Neutral, alkali or acid. Chemicals that are acid reacts with an alkali neutralizing it making water and a salt. Acids commonly are sour tasting.
The purpose of this experiment was to determine the pKa of the bromothymol blue (indicator) through absorption spectroscopy. Bromothymol blue being a monoprotic acid base indicator, displays different colors at different pH because of the differences in the ratio of the conjugated acid and base form. The fraction of conjugate acid and base was interpolated for the solutions through the acquired absorbance spectrum of the bromothymol blue at various pH. The rearranged form of Henderson Hasselbalch equation was graphed as a function of pH to determine the pKa of the indicator.
In this experiment different pH levels ranging from 3 to 11 were used to test the effects on daphnia heart rate. The pH scale ranges from 0 to 14. A pH ranging from 0 to 6 is acidic, a pH of 7 is neutral, and a pH higher than 7 ranging from 8 to 14 is basic. PH revolves around hydrogen ions (H+). The reason pH levels can be acidic, basic, or neutral is because acids give hydrogen ions away while bases accept hydrogen ions. (Decelles, 2002).
My science fair topic will be measuring the acidic levels in different companies of water bottles such as Aquafina, Dasani, Evian, Fiji, Miami Dade Tap Water, Penta, Publix Spring Water, Smart Water, Smart Water, Volvic, Voss, and Zephyrhills. Bottled water has been tested for its ppm (parts per million) to measure the amount of particles inside the water. The pH scale is a measurement of how acidic or basic an aqueous solution is. The pH scale has a range of 0-14; numbers less than 7 are considered acidic and numbers greater than 7 are considered basic. An acidic pH level means that the solution has more free hydrogen ions, and a basic pH level means that the solution has more free hydroxyl ions. pH is reported in logarithmic units and an increase or decrease of one on the pH scale has a 10-fold change. The negative logarithmic of the hydrogen ion concentration calculates the pH level of a solution. This is why pH stands for the potential of hydrogen and it calculate din
By using acid-base titration, we determined the suitability of phenolphthalein and methyl red as acid base indicators. We found that the equivalence point of the titration of hydrochloric acid with sodium hydroxide was not within the ph range of phenolphthalein's color range. The titration of acetic acid with sodium hydroxide resulted in an equivalence point out of the range of methyl red. And the titration of ammonia with hydrochloric acid had an equivalence point that was also out of the range of phenolphthalein.. The methyl red indicator and the phenolphthalein indicator were unsuitable because their pH ranges for their color changes did not cover the equivalence points of the trials in which they were used. However, the
Knowledge Probe: According to.epa.gov/acidrain/measure/pH.html, pH is a measure of the hydrogen ion concentration of a solution. Solutions with a high concentration of hydrogen ions have a low pH and solutions with a low concentrations of H+ ions have a high pH. A pH of 7 is the most neutral you can get and 0 being the most acidic and 14 being the most basic. each level is 10 times more basic/ acidic than the previous level, for example a pH of 8 is 10 times more basic than 7, and a pH of 9 is 100 times more basic than 7. when an acidic substance reacts with a basic substance they counter each other like mixing hot and cold water.
For this experiment, titrations on a weak acid, acetic acid, and a buffer were performed. Acetic acid was titrated with NaOH in order to observe the half-equivalence point as well as the equivalence point. Then, the buffer and the buffered acetic acid solution prepared faced additional titration with NaOH and HCl to evaluate the differing buffering effects following the addition of a strong acid and strong base. Finally, the buffer’s buffering capacity was calculated. If the experiment were to be repeated, it would be interesting to observe the buffering effects following a titration between a weak base and a buffer instead with greater concentrations. The change in the concentration following the preparation of buffer with a weak base and its conjugate acid would pose for an interesting experiment to observe an increase in the buffering capacity.
In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.