Rates Of Reaction Flashcards
What are catalysts ?
Catalysts are substances that speed up chemical reactions without being changed or used up during the reaction.
They also provide a different pathway for a chemical reaction that has a lower activation energy.
What is the rate of a reaction?
How quickly reactants are used up or products are produced
What is the equation for calculating the mean rate of reaction?
mean rate = change in quantity of product or reactant / time taken
What is the unit for rate of reaction in a reaction involving a change in mass?
g/s
What is the unit for rate of reaction in a reaction involving a change in volume?
cm3/s
What is the activation energy?
The minimum amount of energy colliding particles have to have before a reaction will take place
What effect does increasing concentration have on the rate of reaction?
The rate of reaction increases
Why does increasing concentration have this effect?
more reactant particles in the same volume lead to more frequent collisions
What effect does increasing pressure have on the rate of reaction?
The rate of reaction increases
Why does increasing pressure have this effect?
less space between particles means more frequent collisions
What effect does increasing surface area have on the rate of reaction?
The rate of reaction increases
Why does increasing surface area have this effect?
More reactant particles are exposed and able to collide, leading to more frequent collisions
What effect does increasing temperature have on the rate of reaction?
The rate of reaction increases
Why does increasing temperature have this effect?
Particles move faster, leading to more frequent collisions / particles have the same activation energy, so more collisions result in a reaction
How do catalysts increase the rate of a reaction?
They lower the activation energy of a reaction, so more collisions result in a reaction.
