chemistry specification part 3 Flashcards
what is the activation energy
the minimum amount of energy particles need to react when they collide is called activation energy
what happens when you increase the temperature
-particles move faster which leads to a higher frequency of collisions.
-increases the energy in the collisions. reactions only happen If they have enough energy to react so this leads to more successful collisions
what happens when you increase the concentration/pressure
if the solution is more concentrated there are more particles of reactant in the same volume which increases collision frequency so the rate increases.
In a gas increasing the pressure means particles are more crowded which increases collisions
what happens when you increase surface area
(smaller solid particles means higher rate)
if a reactant is broken down into smaller pieces it will increase the surface area to volume ratio. The particles around it will have more area to work on
what is a catalyst
a substance that increases the rate of the reaction without being chemically used in the reaction
how does a catalyst increase the rate of a reaction?
decrease the activation energy needed for a reaction to occur by providing an alternative pathway that has a lower activation energy
how are enzymes used in the production of alcoholic drinks
enzymes from yeast cells are used in the fermentation
They catalyse the reaction that converts sugars into ethanol and CO2
what is breaking bonds
endothermic
what is making bonds
exothermic
how can you measure temperature change when dissolving salts in water
by adding salt to a polystyrene cup of water and measuring the change when the salt has dissolved.
dissolving ammonia chloride decreases the temp of solution-endothermic
dissolving calcium chloride cause temp of the solution to increase-exothermic
