Question

Environmental Chemistry

True/False Statements based on Chapter 10, Part 2

1. During the summertime, lakes will be stratified so that the aerobic conditions are at the bottom and anaerobic conditions are at the top. This due to the warming of the surface water killing all of the aerobic organisms.

2. A low pE value is when electrons are readily available from substances dissolved in water, meaning the medium is reducing.

3. The oxidation of ammonia and ammonium ions occurs in aerobic conditions by plants.

4. During fermentation, both the oxidizing and reducing agents must be organic materials.

Answer 1

Ans 1. True, as the weather gets hotter, the density difference between warm surface water and cold bottom water increases to a point where the two layers do not mix. This phenomenon, called summer stratification and for that nutrients are no longer available for surface organisms. Again cold water contains oxygen and creates aerobic condition at the bottom and anaerobic condition at the top.

Ans 2. False. As medium never gets reduced, it is the material or metal which gets reduced.

Ans 3. True. Oxidation of ammonia occurs in soil in presence of available oxygen.

Ans 4. True. As whole fermentation process is for regeneration of NAD+ and it happens in organic materials only.