Question

Why does Bromothylmol Blue solution turn yellow when carbon dioxide is added? what reation is occuring to turn it yellow?

Answer 1

bromothymol blue + H+ => something yellow

Answer 2

actually... i meant what if the solution was in the dark with an Elodea plant and turned yellow? there was never any CO2 in there.

Answer 3

the elodea plant was in the dark, right?
what do plants do in the dark?
why do plants have mitochondria?

Answer 4

carbon dioxide dissolves into water and makes carbonic acid: \(CO_2 +H_2O \rightleftharpoons H_2CO_3 \)
The acid then reacts with water and forms bicarbonate and hydronium ions
\(H_2CO_3 +H_2O \rightleftharpoons H_3O^+ + HCO_3^-\)

hydronium ions cause bromothymol blue to turn yellow

Answer 5

Peter14- respiration right?

Answer 6

yes

Answer 7

:D if you dont mind can you help me with another one?

Answer 8

sure

Answer 9

How would you demonstrate that Elodea carries out photosynthesis at a faster rate than it carries out respiration?

Answer 10

like a mini experiment of some sort

Answer 11

first: keep your elodea in sunlight
then: put your elodea in a sheltered place with only nonphotosynthetic light (light that doesn't cause photosynthesis)(use light the same color as your elodea) and see how long it is until the color changes
then: put your elodea back in sunlight and see how long it takes until the color changes

Answer 12

thanks so much! :D