Topic 6: Rates of Reactions Flashcards
What is a rate?
-A rate is a measure of change per unit time and has units Is.
What are collisions?
-For a chemical reaction to occur particles need to collide with each other with sufficient kinetic energy to react.
How does adding a catalyst effect the rate of a reaction?
-This is because it increases the rate of the reaction and is not used up.
How does increasing the surface area effect the rate of the reaction?
-The substance is more accessible for particles to react.
How does apply more heat to the reacting increase the rate of the reaction?
-This is because of the fact the particles are moving around quicker therefore there will be more successful reactions.
How does increasing the concentration increase the rate of the reaction?
-This is because there is more of a substance so there will be more successful collisions with sufficient energy.
How does increasing the pressure of the gas increase the rate of the reaction?
-This is because of the fact that compressing the gas gives it more kinetic energy in a smaller space there for there is going to be more successful collisions.
What is collision theory?
-Different reactions can happen at different rates. Reactions that occur slowly have a low rate of reaction. Reactions that happen quickly have a high rate of reaction. For example, rusting is a slow reaction: it has a low rate of reaction. Burning and explosions are very fast reactions: they have a high rate of reaction.
What is a catalysis?
-This ; speeds up a reaction ; remains chemically unchanged ; and lowers energy barrier to reaction. A catalyst increases the rate of reaction by providing an alternative route that has a lower activation energy.
What is the activation energy?
-This is because many reactions need an input of energy to start the reaction off. This is energy is called the activation energy. It is represented on an energy level diagram as the difference between the reactants’ energy level and the top of the curve.
