C8 Rates and Equilibrium Flashcards
1
Q
- Give two ways you can measure the rate of a reaction.
A
- Measure the rate the reactant gets used up or the rate the product is formed (e.g. collect a gas made)
2
Q
- What units are used for rate of reaction if a gas is collected?
A
- cm3/s
3
Q
- In terms of the reactants - when do reactions end?
A
- When the reactants are all used up
4
Q
- What is the collision theory – ‘Reactions only occur when..’
A
‘Reactions only occur when..particles collide with enough energy’
5
Q
- In terms of collisions, why are some reactions faster than others?
A
- More frequent collisions
6
Q
- Why does increasing concentration increase the rate of reaction?
A
- More particles in the same volume so - more frequent collisions
7
Q
- Why does increasing pressure of gases increase the rate of reaction?
A
- More particles in the same volume so - more frequent collisions
8
Q
- Why does breaking reactants up into smaller pieces increase the rate of reaction?
A
- More reactant particles available to collide with so - more frequent collisions
9
Q
- Why does increasing the temperature increase the rate of reaction (two reasons)?
A
Particles move faster so - more frequent collisions AND collide with more energy so - more collisions are successful
10
Q
- What is a catalyst?
A
- A substance that changes the rate of a reaction but is not used up.
11
Q
- Why does adding a catalyst increase the rate of the reaction?
A
- It lowers the activation energy
12
Q
- What is the name given to biological catalysts?
A
- Enzymes
13
Q
- If a reaction is exothermic in the forward direction what can you say about the same reaction in the other direction?
A
- endothermic
14
Q
- What can you about the rate of the forward and backward reactions at equilibrium?
A
- They are the same
15
Q
- What can you say about the amount of products and reactants at equilibrium?
A
- The amount of products and reactants don’t change
