topic 18+19- rates of reaction and energy in reactions Flashcards
Activation energy
The activation energy is the minimum energy with which particles much collide in order to cause a chemical reaction
Four main factors affecting the rate of reaction:
- temperature
- concentration
- pressure
- surface area
On a concentration vs time graph, what tells us the reaction has slowed down?
Smaller gradient (less steep line)
On a concentration vs time graph, what tells us the reaction has sped up?
Larger gradient (steeper line)
On a concentration vs time graph, what tells us the reaction has finished?
no gradient, zero gradient
Catalysts
Substances that increase a chemical reaction’s rate without reducing in quantity during the reaction
What is the catalyst used in the process that makes ammonia?
Iron
How do catalysts increase the rate of reaction?
By lowering the activation energy
Drawbacks of very fast reactions
- can be expensive
- safety concerns
What happens in exothermic reactions?
Energy from the reacting chemicals is transferred to the surroundings
What happens in endothermic reactions?
Energy from the surroundings is transferred to the reacting chemicals
What do exothermic reactions do to the temperature of the surroundings?
Increase the temperature
What do endothermic reactions do to the temperature of the surroundings?
Decrease the temperature
In exothermic reactions:
energy released by forming bonds > energy required to break bonds
>
In endothermic reactions:
Energy released by forming bonds > energy required to break bonds
