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