What is the molecule upon which an enzyme act

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

Consider the following reaction at equilibrium. 2co2 (g) 2co (g) + o2 (g) h° = -514 kj le châtelier's principle predicts that the equilibrium partial pressure of co (g) can be maximized by carrying out the reaction a. at high temperature and high pressure b. at high temperature and low pressure c. at low temperature and low pressure d. at low temperature and high pressure e. in the presence of solid carbon

Which of these is a physical property