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