c6 rates of reaction Flashcards
when do chemical reactions take place
when the reacting particles collide with each other. The collisions must also have sufficient energy for the reaction to take place
how are chemical reactions determined
by the frequency of successful collisions
activation energy
the minimum amount of energy that particles must have in order to react
what is a catalyst
increases the rate of reaction but are not used up in the reaction
what do catalysts allow
reactions to be carried out quickly without needing to increase temp or pressure, saving money during chemical production
what happens when a catalyst is not used up
it can be used again and again
what do rate of reaction depend on
the number of particles that have enough energy to cross the activation energy barrier and collide successfully
how can catalysts increase rate of reaction
by lowering the activation energy required for a successful collision to take place
what happens when a catalyst is present
the particles require less energy to cross the activation energy barrier increasing rate of reaction
where is a catalyst placed in an equation
above the arrow to show its presence
industrial uses of catalysts
-removal of combustion pollutants from car exhausts
-cracking of hydrocarbons
-production of ammonia
what does the double arrow show in an equation
the reaction is reversible, the direction of the reaction can be altered by changing the conditions
what happens when hydrated copper sulfate is heated
it decomposes to form anhydrous copper sulfate and water - endothermic
what happens if water is added back to anhydrous copper sulfate
a lot of energy is released and the reaction mixture gets hot, reversing the reaction - exothermic
a reaction that is endothermic..
will be exothermic in the erverse direction - the same amount of energy will be transferred
what is equilibrium
a state in a reaction where the rate of the forward reaction is equal to the rate if the reverse reaction
what happens if a reaction occurs in a sealed container
the reactants and products could not escape, the left and right reaction would occur at the same time
le chatelier’s principle
if a system is at equilibrium and a change is made to the conditions e.g. temp, the system will counteract the change
