Catalysts and Inhibitors

Catalyst: Catalyst: Speeds up a reaction by lowering the Speeds up a reaction by lowering the activation energy barrier activation energy barrier Is not used up in the reaction, can be Is not used up in the reaction, can be retrieved once the reaction is complete retrieved once the reaction is complete Inhibitor: Inhibitor: Slows down reaction by increasing the Slows down reaction by increasing the activation energy barrier or by interfering with a activation energy barrier or by interfering with a catalyst catalyst

Catalytic Converter

The first part of the catalytic converter uses platinum and rhodium to help reduce the NO emissions. The first part of the catalytic converter uses platinum and rhodium to help reduce the NO emissions. 2NO (g) => N 2(g) + O 2(g) or 2NO (g) => N 2(g) + O 2(g) or 2NO 2(g) => N 2(g) + 2O 2(g) 2NO 2(g) => N 2(g) + 2O 2(g) - When an NO or NO 2 molecule contacts the catalyst, the - When an NO or NO 2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and catalyst rips the nitrogen atom out of the molecule andatom holds on to it holds on to it - The oxygen is then freed in the form of O 2 - The oxygen is then freed in the form of O 2 - The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N 2 - The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N 2

The second part of the converter uses platinum and palladium which aids the reaction of the CO and hydrocarbons with the remaining oxygen. : The second part of the converter uses platinum and palladium which aids the reaction of the CO and hydrocarbons with the remaining oxygen. : 2CO (g) + O 2(g) => 2CO 2(g) Honeycomb catalyst structure in a catalytic converter

Types of Catalysts Heterogeneous Catalyst: A catalyst that is in a different phase or state as the reaction which it is catalyzing A catalyst that is in a different phase or state as the reaction which it is catalyzing ex. Palladium, Platinum and Rhodium metal in catalytic converter reacting with gases ex. Palladium, Platinum and Rhodium metal in catalytic converter reacting with gases Homogeneous Catalyst: A catalyst that is in the same phase or state as the reaction which it is catalyzing, usually this occurs when catalyst is dissolved with reactants A catalyst that is in the same phase or state as the reaction which it is catalyzing, usually this occurs when catalyst is dissolved with reactants ex. KI in Hydrogen Peroxide decomposition demo ex. KI in Hydrogen Peroxide decomposition demo

Enzyme Catalysts Speed up reactions without being used up by lowering activation energy Catalyze reactions within the body necessary for digestion and cellular respiration

Inhibitors Inhibitors are necessary in the body to slow down reactions when the bodies needs have been met Some inhibitors are poisonous to the body and bond irreversibly to enzymes preventing the enzyme from catalyzing reactions

Inhibitor slows down reaction by increasing the activation energy Catalyzed reactionUncatalyzed reactionInhibited reaction

Classes of Inhibitors Reversible – hydrogen bonds or bonds ionically Irreversible – bind covalently with active site and modify the enzyme

Famous Cases of Poisoning Grigory Rasputin – Failed cyanide poisoning Napoleon Bonaparte – Arsenic poisoning

Grigory Rasputin The ‘Mad Monk’

Rasputin Lyrics Artist: Boney M. There lived a certain man in Russia long ago He was big and strong, in his eyes a flaming glow Most people looked at him with terror and with fear But to Moscow chicks he was such a lovely dear He could preach the bible like a preacher Full of ecstasy and fire But he also was the kind of teacher Women would desire RA RA RASPUTIN Lover of the Russian queen There was a cat that really was gone RA RA RASPUTIN Russia's greatest love machine It was a shame how he carried on He ruled the Russian land and never mind the czar But the kasachok he danced really wunderbar In all affairs of state he was the man to please But he was real great when he had a girl to squeeze For the queen he was no wheeler dealer Though she'd heard the things he'd done She believed he was a holy healer Who would heal her son

But when his drinking and lusting and his hunger for power became known to more and more people, the demands to do something about this outrageous man became louder and louder. "This man's just got to go!" declared his enemies But the ladies begged "Don't you try to do it, please" No doubt this Rasputin had lots of hidden charms Though he was a brute they just fell into his arms Then one night some men of higher standing Set a trap, they're not to blame "Come to visit us" they kept demanding And he really came RA RA RASPUTIN Lover of the Russian queen They put some poison into his wine RA RA RASPUTIN Russia's greatest love machine He drank it all and he said "I feel fine" RA RA RASPUTIN Lover of the Russian queen They didn't quit, they wanted his head RA RA RASPUTIN Russia's greatest love machine And so they shot him till he was dead (Spoken:) Oh, those Russians...

Poisons that Disrupt Cellular Respiration Five complexes are involved in cellular respiration to produce energy Cyanide binds irreversibly to Complex IV (cytochrome oxidase)

Napoleon Bonaparte

Arsenic Poisoning Interferes with essential metabolic enzymes by inhibiting their function Affects brain and neurological function leading to multi-organ failure