C8 - Rates And Equilibrium Flashcards
What are the two ways of working out the rate of a chemical reaction?
How quickly the reactants are used up or how quickly the products of the reaction are made.
What is the collision theory?
Reactions can only take place when the particles of reactants come together. Thr reacting particles do not only have to bump into each other, but also need to collide with enough energy to cause a reaction to take place.
Define Activation energy
The minimum amount of energy that particles must have before they can react.
Reactions are more likely to happen between reactant particles if you?
Increase the frequency of reacting particles colliding with each other or by increasing the energy they have when they collide.
By increasing the number of collisions in a certain time and the energy of collisions, you?
Increasing the number of collisions in a certain time and the energy of collisions produces faster rates of reaction.
What does a larger surface area result in?
A larger surface area results in an increased frequency of collisions.
How do you work out the mean rate of reaction?
Mean rate of reaction =
Quantity of reactant used / time
Or
Quantity of product formed / time
Increasing the temperature increase the rate of reaction because?
The particles collide more often or / and particles collide with more energy.
What happens when you heat up a substance?
When you heat up a substance, energy is transferred to its particles. In solutions and in gases, this means that the particles move around faster. When particles move around faster, they also collide more often. This means there is more chances for them to react.
What happens if particles move around more quickly?
Particles that move around more quickly have more energy. This means that any collisions they have are much more energetic.
How can you increase the frequency of collisions between particles?
Increasing the concentration and pressure.
Define catalyst
A substance that speeds up a chemical reaction by providing a different pathway for the reaction that has a lower activation energy. The catalyst is chemically unchanged at the end of the reaction.
What is a reversible reaction?
A reaction that can happen two ways. (It can be reversed) When reversed, the reaction will make the same original reactants.
What happens to energy during reversible reactions?
During reversible reactions, if the reaction transfers energy to the surroundings when it goes in one reaction, it will take in exactly the same amount of energy from the surrounding when it goes in the other direction.
Define closed system
A system in which no matter enters or leaves.
