Edexcel C2 Rates Of Reaction

• Higher Concentration INCREASES COLLISIONS.
• Makes COLLISIONS between particles MORE LIKELY.
• In a gas, increasing pressure means particles are MORE SQUASHED UP which means there will be MORE FREQUENT COLLISIONS.

• When the TEMPERATURE is INCREASED the particles all MOVE QUICKER
• If they're moving quicker there will be MORE FREQUENT COLLISIONS

• If one of the reactants is a SOLID then BREAKING IT UP into SMALLER PIECES will INCREASE ITS SURFACE AREA.
• This means that particles around it in the solution will have A LARGER AREA TO REACT WITH resulting in MORE FREQUENT COLLISIONS

• A SOLID CATALYST works by giving the REACTING PARTICLES a SURFACE to STICK TO
• They increase the number of SUCCESSFUL COLLISIONS by lowering the ENERGY particles needed to start reacting with eachother (Activation Energy)

• HIGHER TEMPERATURE also increases the ENERGY of the collisions, as if makes the particles move FASTER.
• Reactions ONLY HAPPEN if the particles collide with ENOUGH ENERGY
• This is because there's a MINIMUM ENERGY needed to  break the INITIAL BONDS.
• At a HIGHER TEMPERATURE there are MORE PARTICLES colliding with ENOUGH ENERGY to make the reaction happen. 

• Slowest= Rusting of iron
• Moderate= a metal reacting with an acid to produce a gentle stream of bubbles
• Fast= An explosion, which is all over a fraction of a second

• A catalyst is a substance which changes the speed of a reaction, without being used up in the reaction.
• A catalyst lowers the energy required by the reactants to react.
• Makes it easier for the reactioon to happen as it increases the rate of reaction
• Means that a lower temperature can be used, without the rate of reaction dropping.

Catalytic Converters are used in Vehicle Exhausts

• Vehicle exhausts can give off poisonous gasses like carbon monoxide if petrol doesn't burn properly.
• A catalytic converter is used in the exhaust pipe. It increases the rate at which carbon monoxide and unburnt fuel in exhaust gasses react with oxygen in the air to produce carbon dioxide and water
• Catalyst has a large surface area which works best at high temperatures to increase RoR