Posted: June 15th, 2022

How did the color of the bromthymol blue solution

CARBON DIOXIDE PRODUCTION BY GERMINATING SEEDSINTRODUCTION:Living things need energy to carry on most of their processes. The cells of germinating seeds oxidize carbohydrates, in the process known as cellular respiration, to provide energy for growth. In this process, carbon dioxide is released as a byproduct. The balanced equation for cellular respiration (oxidation of glucose) is as follows:C6H12O6 + 6 H2O + 6 O2 —> energy + 6 CO2 + 12 H2OThe increasing concentration of carbon dioxide, in a closed environment, can be observed using a pH indicator solution. As carbon dioxide dissolves in water, it produces carbonic acid. As the carbonic acid concentration increases, the pH lowers.In this lab, you will observe the formation of carbon dioxide by germinating seeds using bromthymol blue solution as the indicator. As more carbon dioxide is absorbed, and the pH lowers, bromthymol blue turns from blue to green to yellow.MATERIALS:50 Pea seeds for sprouting2 one-quart jars with airtight lidsBeaker or small jar to soak seedsPaper towels2 test tubesBromthymol blue solutionWaterPRE-LAB:Soak the pea seeds for 24 hours before the lab.PROCEDURE:1. Obtain 2 one-quart jars with airtight lids and place several layers of moist paper towels in the bottom of each jar.2. Place 50 presoaked peas in the first jar. Fill 2 test tubes half full of bromthymol blue solution, and stand 1 tube in each jar.3. Place the lids on the jars tightly and keep the jars on a shelf or table, undisturbed, at room temperature. Figure 1 shows the test jar, and figure 2 shows the control.4. Observe the jars each day, and record the color changes of the bromthymol blue on your DATA TABLE. Remember, the observation after the jars are set-up, is for day zero.DATA TABLE: Carbon Dioxide Production by Germinating Seeds.DateJar with Peas(test jar)Jar without Peas(control)Day zeroblueblueANALYSIS:Question 1. How did the color of the bromthymol blue solution in your test jar change over time?Question 2. What can be inferred from the change observed in question 1?Question 3. Was there a color change in the control jar (the jar with no seeds)?Question 4. What can be inferred from the change observed in question 3?Question 5. Why was it necessary to have a control for this experiment?

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