Questions are worth 2 points each. NO 3 - and N 2 .
Ligands are functional groups that attract and bind metallic ions to organic matter.
The origin of the residue is identifiable, but this is not true for soil organic matter. Soil organic matter gives the soil a light color while plant residues give it a very dark color. Most of the fractions of soil organic matter can be dissolved in a strong base. None of the above will form a precipitate. The Haber-Bosch process for making ammonia combines nitrogen and hydrogen under pressure and at high temperatures.