C8.3 - The effect of temperature Flashcards
What happens when you increase the temperature?
When you increase the temperature, it increases the rate of reaction
What can you use to reduce the temperature and slow down the rate of reaction?
You can use fridges and freezers to:
- Reduce the temperature
- Slow down the rate of reaction
When food goes off, it is because of what?
When food goes off, it is because of chemical reactions
When food goes off, it is because of chemical reactions, so what does reducing the temperature do?
When food goes off, it is because of chemical reactions, so reducing the temperature slows down these unwanted reactions
What tells you why raising the temperature increases the rate of a reaction?
Collision theory tells you why raising the temperature increases the rate of a reaction
Collision theory tells you why raising the temperature increases the rate of a reaction.
What are there?
There are 2 main reasons, particles collide:
- More often
- With more energy
What happens when you heat up a substance?
When you heat up a substance, energy is transferred to its particles
When you heat up a substance, energy is transferred to its particles.
What does this mean in solutions and in gases?
In:
1. Solutions
2. Gases
,this means that the particles move around faster
When you heat up a substance, energy is transferred to its particles.
In solutions and in gases, this means that the particles move around faster.
What happens when particles move around faster?
When particles move around faster, they also collide more often
What happens when particles react more frequently?
When particles react more frequently, there are more chances for them to react
When particles react more frequently, there are more chances for them to react.
What does this do?
This increases the rate of reaction
What do particles that are moving around more quickly have?
Particles that are moving around more quickly have more energy
Particles that are moving around more quickly have more energy.
What does this mean?
This means that any collisions they have are much more energetic
What happens when you increase the temperature of a reacting mixture?
When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time
When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time.
Why is this?
When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time, because a higher proportion of particles have energy greater than the activation energy
What does an increased proportion of particles exceeding the activation energy do?
An increased proportion of particles exceeding the activation energy has a greater effect on rate than the increased frequency of collisions
What happens around room temperature, if you increase the temperature of a reaction by 10 degrees Celsius?
Around room temperature, if you increase the temperature of a reaction by 10 degrees Celsius, the rate of the reaction will roughly double
Describe the particles in a cold reaction
The particles in a cold reaction:
- Slow movement
- Less frequent collisions
- Little energy
Describe the particles in a hot reaction
The particles in a hot reaction:
- Fast movement
- More frequent collisions
- More energy
Example results for an investigation on the effect of temperature on the rate of a reaction.
What does the negative slope show?
The negative slope shows that as the temperature increases, the time it takes for the reaction to finish decreases
Example results for an investigation on the effect of temperature on the rate of a reaction.
The negative slope shows that as the temperature increases, the time it takes for the reaction to finish decreases.
However, what happens as the temperature increases?
As the temperature increases, the: 1. Rate of the reaction Or, 2. 'Mean rate of reaction' also increases
