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What do they mean by rate of chemical reaction
How quickly the reactants are converted into products
Formula for rate
Rate = mass of product produce or lost / time taken
Rate = volume of product produced or lost / time taken
What is precipitation
Measures the time it take for a mark to disappear
What is colour change
Measure the time it takes for a colour change to occur
What are the problems with precipitation and colour change
Can’t plot results on a graph
Its subjective - people might interpret the colour change differently
How do you calculate the rate of a reaction by measuring the change in mass
Use a balance to monitor how the mass change over time
Take measurements at regular intervals
Plot results on a graph
Calculate the gradient
How can you use a gas syringe to measure the rate of a chemical reaction
The gas syringe measures how the volume of gas changes over time
Take measurements at regular intervals
Plot your results on a graph
Calculate the gradient
5 factors that affect the rate of a chemical reaction
Temperature
Concentration
Pressure
Surface area
Catalyst
What happens to the rate of the reaction when the temperature increases (explain what happens to the particles)
Rate of reaction increases
The particles move around faster which makes them collide more frequently
This will make them collide with more energy so the collisions is more likely have endowing energy to react successfully
What happens to the rate of the reaction when concentration or pressure increases (explain what happens to the particles)
Rate of reaction will increase
The number of particles per unit of volume will increase which will make the collision frequency increase
What happens to the rate of the reaction when the surface area of a solid increase (explain what happens to the particles)
Breaking the solid into smaller pieces increases the surface area to volume ratio
With the same volume of solid the particles will have a greater area which they can more frequently collide re
What is the collisions theory
For particles to react the have to collide with sufficient energy and right direction
What is activation energy
Minimum amount of energy that particles requires to react together
Why do particles need activation energy
To break the bonds of the reactants to begin the reaction
How does a catalyst increase the rate of reaction
Lowering the activation energy required for a reaction giving it an alternative route
It requires less energy to react
Why do concentration/time graphs plateau
The reactants are used up
How do you find the gradient of a line
Gradient = change in y / change in x
How do you find the rate of reaction at a particular point on a concentration/time graph
Draw a tangent to the line at that point
Pick 2 points on the line and do the change in y / change in x
The gradient is the rate
What is reversible reaction
A reaction that can go backwards and forwards
What happens to the reactants during the reaction
Concentration of reactants fall which slows down the forward reaction
Concentration of product rises speeding up the backwards reaction
What does equilibrium mean
The rate of forward reaction is equal to the tar of the backward reaction
What does dynamic equilibrium mean
When both forward and backward reaction are happening but there is no overall affect since they are at the same rate
Products is breaking down as quickly as it is being formed
What condition is required for a reaction to reach equilibrium
Closed system
What does it mean if the position of equilibrium lies to the right
The products concentration is greater than the reactants
Factors that change the position of equilibrium
Temperature
Pressure
Concentration of reactiants and products
What is Le Chateliers principle
The system will counter the change in conditions in order to restore equilibrium
Why is Le Chatelier principle useful
It helps us predict the affect of changes made to the system
According to Le Chatelier principle what happens if you decrease the temperature
The position of equilibrium will shift towards the exothermic side to produce more heat
According to Le Chatelier principle what happens if you increase the pressure
The position of equilibrium will shift to the side with less molecules of gases to reduce pressure
According to Le Chatelier principle what happens if you decrease the concentration of the reactants
The position of equilibrium will shift to the left to increase the reactant concentration
Note 
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