C8 - Rates of Reaction Flashcards
C8 - what is meant by collision theory?
Reactants are colliding all the time.
Sometimes when they collide, they do not have enough energy to break existing bonds. NO REACTION.
Once reactants have enough energy, they collide faster, harder and more often.
Existing bonds are broken and products are formed. REACTION.
C8 - Explain in terms of particles, how and why the rate changes over the course of a reaction.
Rate at the start is fast because reactant concentration is high.
Lots of successful collisions.
Over the course of the reaction the reactants get used up.
Their concentration goes down.
Frequency of successful collisions decreases.
Rate of reaction slows down towards the end.
C8 - Describe and explain the effect of temperature on rate of reaction.
- Increasing temperature increases rate of reaction.
- Reacting particles have more kinetic energy.
- More successful collisions per second.
C8 - Describe and explain the effect of pressure on rate of reaction.
- Increasing pressure increases the rate of reaction.
- Particles have less space to move around in without colliding.
- More successful collisions per second.
C8 - Describe and explain the effect of concentration on rate of reaction.
- Increasing concentration increases the rate of reaction.
- The likelihood of particles colliding increases.
- More successful collisions per second.
C8 - Describe and explain the effect of surface area on rate of reaction.
- Increasing surface area increases rate of reaction.
- The likelihood of particles colliding increases.
- More successful collisions per second.
C8 - Describe and explain the effect of adding a catalyst.
- Adding a catalyst increases the rate of reaction.
- A catalyst is a substance that provides an alternative pathway for the reaction to occur.
- This pathway has a lower activation energy.
- A higher proportion of particles are at the required energy for the reaction to start.
C8 - Explain why catalysts are useful in industrial processes.
- They can be reused.
- Products can be made more quickly, saving time and money.
- They reduce the need for high temperatures.
- They save fuel and reduce pollution.
C8 - What is a reversible reaction?
Reversible reactions occur when the backwards reaction (products → reactants) takes place relatively easily under certain conditions.
The products turn back into the reactants.
C8 - Explain what is meant by dynamic equilibrium.
When the forwards and backwards reaction happen at exactly the same rate.
The concentration of reactants and products will be constant.
C8 - Describe the effects of increasing the pressure on the position of equilibrium.
If pressure is increased, equilibrium will shift towards the side of the equation that produces fewer gas molecules.
The reaction that produces fewer gas molecules will speed up.
This is to minimise the effect of increasing pressure.
C8 - Describe the effects of decreasing the pressure on the position of equilibrium.
If pressure is decreased, equilibrium will shift towards the side of the equation that produces more gas molecules.
The reaction that produces more gas molecules will speed up.
This is to minimise the effect of decreasing the pressure.
C8 - Describe the effects of increasing the temperature on the position of equilibrium.
If temperature is increased, equilibrium will favour the endothermic reaction
The endothermic reaction will speed up.
This is to minimise the effect of increasing the temperature.
C8 - Describe the effects of decreasing the temperature on the position of equilibrium.
If temperature is decreased, equilibrium will favour the exothermic reaction.
The exothermic reaction will speed up.
This is to minimise the effect of decreasing the temperature.
