Catalysts Flashcards
What is the use of a catalyst in a reaction?
It can provide a surface for reactions to take place on. Reactant molecules are held at a favourable angle for collisions to occur, increasing successful collisions and increase the speed of a reaction.
What is a homogeneous catalyst?
The catalyst is in the same state as the reactants (usually that of solution)
What is a heterogeneous catalysis?
The catalyst is in a different state from the reactants
What are enzymes?
They’re biological catalysts. They’re complex protein molecules which speed up specific chemical changes by homogeneous catalysts
What is a main use of catalysts?
Catalytic converters in the exhaust systems of a car. They’re needed to change harmful gases into less harmful gases
What does a catalyst provide for a reaction?
It provides an alternative reaction pathway which involves less energy and so the catalyst lowers the activation energy
. It doesn’t affect the reactants or products, so the enthalpy change stays the same
What are some examples of catalysts used in industry?
. Iron- used to make ammonia by the Haber process
. Platinum- used in manufacture of nitric acid by the Ostwald process
. Rhodium/Platinum- in catalytic converters
. Nickel- to make margarine by hardening vegetable oil
. Vanadium (V) Oxide- in the contact process, to make sulfuric acid
What is a catalyst?
. They speed up chemical reactions without being used up
. It alters the rate of reaction, allowing it to be done at a lower temperature. Therefore, used in the chemical industry to make manufacturing processes more economical.
How do catalysts work?
. It lowers the activation energy (by forming temporary bonds with reactants and causes the bonds within the reactants to weaken)
. This increases the number of molecules with the minimum kinetic energy required. This increases the number of successful collisions, therefore increasing the rate of reaction.
