biology hw need some help?
Critical Thinking/Discussion Questions
1. Explain how one might use bromthymol blue and phenolpthalein to test the pH of water in a swimming pool
2. Critically evaluate this statement: “It’s paranoid and ignorant to worry about industry or agriculture contaminating the environment with chemical wastes; this stuff is just made of the same atoms that were already present in our environment.”
1. Brom-thymol blue turns yellow in the presence
of an acid(pH<7). As it changes from blue to yellow it shows intermediate colors; blue-green,yellow-green ,depending upon how strong the acid is (how low the pH is).
Pheno(whatever...) indicates the presence of a base (alkaline).
It is colorless at neutral pH (7). In a slightly basic solution (a little higher pH than 7) it will change to a pinkish color. In a stronger base it will turn a purplish, wine color indicating a base perhaps in the pH range of 9,10 or higher.
2.Yes, the same atoms ,but rearranged into molecules that are perhaps toxic or even fatal. Example : many farm animals in a small area eat foods containing C, H , O and N, like in proteins. The waste is still made up of the same atoms, but rearranged into a compound called urea. Don't think that you want this in your well water!
Funny stuff – 2