Why does the amount of energy available change as you move from one trophic level to the next?

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?

In the reaction h2co3 (aq) + 3nh3 (aq) = 2 nh4+ (aq) + co3 2-, how many electrons are transferred?

2-bromo-2-methylbutane undergoes an e1 elimination reaction in the presence of ethanol. in the next reaction only one of the possible products is represented. although the product shown is not the major product of the reaction, notice that there is more than one way it can be produced. complete the mechanism and draw the missing substances.