C8 - Rate Of Reactions Flashcards
How does a catalyst speed up a reaction?
By lowering the activation energy
What does ‘the rate of a chemical reaction’ mean specifically?
How fast the reactants are changed into products
What does the collision theory suggest?
The rate of a chemical reaction depends on:
- Collision frequency
- The energy transferred during a collision
What does the collision frequency in the collision theory suggest?
The more collisions there are in a reaction, the faster the reaction
What are 5 things that affect the rate of reaction?
Temperature
Concentration gradient
Preussire of a gas
Surface area
A ctalyst
How does an increased temperature affect the rate of a reaction?
Increased temp –> particles move faster –> particles collide more frequently and a higher chance of reaction
However enzymes can denature
How does an increased concentration of a solution affect the rate of a reaction?
Collisions between particles are more frequent as more particles occupy a small volume
What is the simple equation to find the rate of reaction?
(Amount of reactant used / product formed) divided by time
What are three physical ways you can measure the rate of reaction?
Precipitation and colour change
Change in mass
The volume of gas given off
You can measure the rate of reaction physically using precipitation and colour change. How?
Record how long it takes for an ‘X’ mark, under a reacting solution, to become visible
If the equilibrium lies to the RIGHT, the concentration of __________ is greater than that of the __________
Products
Reactants
If the equilibrium lies to the LEFT, the concentration of __________ is greater than that of the __________
Reactants
Products
What does the equilibrium position depend on?
The temperature
The pressure (if its a gas)
Concentration of reactants and products
What does it mean if a system is at equilibrium?
Both the forward and reverse reactions are happening at the same rate
In a reversible reaction, if the reaction is endothermic in one direction, what will the other direction be?
Exothermic
What is Le Chatelier’s Principle?
That if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract that change
