Rates Of Reaction Y9 Flashcards
Particles react when:
They collide with sufficient kinetic energy, a quantity known as ACTIVATION ENERGY
What is activation energy?
Minimum amount of energy required to break bonds in reactant particles-which leads to particles reacting when they collide
What happens if particles collides but they do not have activation energy?
Collision is unsuccessful and do not lead to a chemical reaction
How can a chemical reaction be altered ?
By changing how often particles collide and with how much energy
ways rate of reaction can be changed?
There are 4 ways
1. Changing temperature of reaction
2. Changing concentration of solutions
3. Changing surface area of a solid reactant
4. Adding a catalyst
Other ways to write activation energy
Ea
Eact
What does increasing the temperature do to the reaction?
Gives all particles more energy so they move around more quickly
This means an increased proportion of particles have activation energy.
Therefore an increase in temperature leads to More Frequent Successful Collisions
Does increasing the temperature increase of decrease the rate of reaction
Increase
What does increasing the concentration of solutions do to the rate of reaction?
This means there will be more particles in a given volume
Therefore there will be More Frequent Successful Collisions between particles.
This increased rate of collision means that there will be more collisions with activation energy
Does increasing concentration of solutions increase or decrease the rate of reaction?
Increase
What does increasing the surface area of a solid reactant do to the rate of reaction?
Pieces will have a larger surface area:
There will be more contact between particles of solid and particles of solutions
More collisions are possible so more collisions with activation energy take palace.
Rate of reaction increase
Does increasing surface area of a solid reactant increase or decrease rate of reaction?
Increase
Definition of a catalyst
A catalyst speeds up the rate of reaction and is unchanged chemically at the end of the reaction
Do catalysts change?
Remain unchanged at the end of the reaction
How much of a catalyst is needed?
Only small amounts
Do all catalyst work for all reactions?
No certain catalyst are used for different reactions
What does a catalyst do?
It gives the reaction an alternate pathway, a path that requires less energy.
The activation energy is lowered so more particles can react on collision and therefore the rate of reaction is faster
What is an enzyme?
A biological catalyst and are proteins
Where are enzymes found?
In living cells
What are the differences between chemical catalysts and enzymes?
Enzymes are much more specific- one enzyme can change the rate of reaction and is
What are enzymes used in?
Brewing
Baking bread
Making biological detergents
Making cheese and yogurt
Making soft centered chocolate
