organic solvents acyl substrates protons organic chemistry hydrogen alkyne electron acceptor activation energy catalysts hydrogen peroxide cell cycles joules chemicals organic reactions electrophile chirality selectivity alkene hydrogen gas concentration Organic single step byproducts constituents phosphate salicylic acid temperatures sodium metabolism reagent dna molecule transition state reactants glucose amino acids nucleophile chemical reaction cesium esters intermediates chromosomes synthesis molecule molecules covalent bonds dehydration room temperature acetone aspirin electron density diels alder reaction atom proteins alcohols atomic mass cytosine journal article alcohol cis junior chemistry methanol isomer carbons living organisms ketone carbon atoms carbon dioxide equilibrium ethers reagents protons neutrons and electrons correlation catalytic hydrogenation water molecules solvent alkenes highest energy oxidation derivatives pyruvate presence hydrogen bonds local anesthetic heat flow chemical reactions krebs cycle exothermic reaction atoms cells chemistry electron pair acids and bases atomic weights electrons dehydration reaction ammonia thymine racemic mixture catalyst