The pH is a measure of the concentration of the hydrogen ion (H+) in water. Highly acidic water has a very high H+ concentration, while basic water has very low H+ concentrations. The pH scale is a logarithmic scale, such that a difference of one pH unit means a 10-fold difference in H+ concentration. The mathematical relationship between pH and H+ concentration ([H+]) is

pH = –log [H+] OR [H+] = 10-pH where [H+] is in moles per liter.

Use a scientific calculator to calculate [H+] for the following pH values:

7 (a neutral solution)

5.6 (unpolluted rainwater)

3.7 (first acid rain sample in North America)

How many times higher is the concentration of H+ in the Hubbard Brook sample than in unpolluted rainwater?

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.