CHEMICAL PHENOMENA IN LIFE 



Such reactions are called Bimolecular Reactions 

 or Reactions of the Second Order. Many reactions 

 in living cells follow the law of these reactions. 

 Reactions of a higher order are not as yet known 

 from living cells. We may at least be certain 

 that the great majority of all reactions in living 

 matter are not connected with the chemical 

 change of more than two different substances. 



In molecular reactions we generally meet with 

 the peculiarity that the reaction is not quite com- 

 pleted when the reaction velocity has reached the 

 value of 0. A certain quantity of the original 

 substance always remains and never disappears. 

 Molecular reactions are consequently incomplete. 

 Thus a small quantity of cane sugar remains un- 

 changed when cane sugar is split by means of 

 diluted hydrochloric acid, and in the same way 

 some quantity of the unsplit ester remains when we 

 split it by means of acid into alcohol and acid. 

 This remarkable phenomenon becomes quite clear 

 if we suppose that the two reactions always take 

 place in opposite directions. Simultaneously with 

 splitting up begins the synthetical reaction, and 

 synthesis increases in proportion as the splitting 

 of the compound advances. The velocity of the 

 splitting process decreases at the same rate as the 

 velocity of the recomposing process increases. 

 At a certain time both processes have the same 

 velocity. No further change takes place in the 

 chemical system, provided that nothing is taken 

 <. So 



