Question

ercise 3A 8. What is actually diffusing blocks? [Hint: It causes the color change of the agar into the agar blocks] 9. Keep the following on your control for the experiment the A. The agar questions in mind when deciding 1 x 10-7. If you calculate blocks start with a concentration of H+ ions of pH, is it acidic, basic or neutral? B. hat other common substance concentration of H+ as the agar blocks has a similar at the beginning of the experiment? C. If the concentration of H+ ions inside of a cell equals the concentration of H ions outside of a cell, what happens to the diffusion of H+? D. Therefore, the color of the agar block will be 10. What is the purpose of a trial in an experiment?

11. Explain what will be put in each beaker, including solution and size of agar cubes.

-Beaker 1:

-Beaker 2:

-Beaker 3:

-Beaker 4:

12. To save time you will do more than one trail of the experiment at the same time. The beakers numbered _______ are the trails and the beaker numbered _______ is the control.

(Fill in the blanks)

13. A timer tell you the number of minutes and seconds that have passed, but you must record the number of minutes in Table 2.

7min 15sec = ___________ min

(Fill in blank)

Answer 1

Method

1. Cut cubes of agar to the following dimensions (use a knife and tweezers to make each as accurate as possible): 5, 10, 15, 20 mm³.
2. Add enough dilute hydrochloric acid to a test tube or small beaker so that when one of the agar blocks is placed in it, it will be totally submerged.
3. Place one of the agar blocks into the test tube or beaker containing the hydrochloric acid, and immediately start timing.
4. Record in a table, how long it takes for all the red colour in the block to disappear (indicating the time it takes the acid to reach the centre of the block).
5. Repeat for all the other block sizes.
6. If time allows, repeat the experiment as many times as possible.

Here,we can two either 2 sizes,such as 5 mm in 2 beakers and 20mm in 2 beakers.

so, beaker 1:dilute Hcl+5 mm agar cubes+phenol red

beaker 2:5 mm agar cubes+phenol red

beaker 3:dilute Hcl+20 mm agar cubes+phenol red

beaker 4:20 mm agar cubes+phenol red

12.beaker 1 and 3 are samples and 2 and 4 are controls.

13.7.15 min

8.dil Hcl is diffusing into agar blocks which converts the phenol red to yellow.

10.to minimise the errors,especially to find out the agar cubes have some sort of pH changes in them

Answer 2

7). The colour change in the agar occurs due to the phenolphtaline indicator, which appears yellow under acidic and pink under basic conditions. As the acidic vinegar diffuses through the agar, the colour change occurs to yellow.