rates of reaction Flashcards
What is the collision theory?
The higher the collision frequency of reacting particles, the faster the reaction.
What are the 4 factors that increase rate of reaction?
~Increased temperature
~Increased concentration/pressure
~Increased surface area
~Catalysts
Why does increased temperature increase the rate of reaction?
Particles move faster with more energy (leading to more frequent and successful collisions).
How does increased concentration or pressure increase the rate of reaction?
As there are more particles in the same volume/space (so collisions are more frequent).
How does increased surface area increase the rate of reaction?
Smaller pieces increase the surface area to volume ratio which gives particles more area to work on (more collisions).
How do catalysts increase the rate of reaction?
By decreasing the activation energy and providing an alternative reaction pathway.
What is the equation for rate of reaction?
Amount of reactant used or amount of product formed
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Time
What are the 3 ways of measuring rate of reaction?
~Precipitation and colour change
~Change in mass
~The volume of gas given off
What is dynamic equilibrium?
When the forward and backward reactions occur at the same rate in a closed system.
If equilibrium lies on the right…
The concentration of the products is greater than the concentration of the reactants.
If equilibrium lies on the left…
The concentration of the reactants is greater than the concentration of the products.
What 3 factors does the position of equilibrium depend on?
~Temperature
~Pressure in gases
~Concentration of reactants and products
What does an endothermic reaction do?
Takes in energy from the surroundings.
What does an exothermic reaction do?
Releases energy to the surroundings.
What does anhydrous mean?
Without water.
What is Le Chatelier’s principle?
If you change the conditions of a reversible reaction at equilibrium, the system will try to counteract the change.
What is Le Chatelier’s principle used to predict?
The effect of changes.
Where and why will the equilibrium move if you decrease temperature?
Will move in the exothermic direction to produce more heat.
What is the result of decreasing the temperature at equilibrium?
There will be more products for the exothermic reaction and fewer for the endothermic reaction.
What does equilibrium do when you increase the pressure?
Equilibrium tries to reduce it by moving in the direction where there are fewer gas molecules.
What does equilibrium do when concentration of the reactants is increased?
Tries to decrease the concentration by making more products.
What does equilibrium do when the concentration of the products is decreased?
Tries to increase concentration by reducing the amount of reactants.
