Chapter 8 - Chemistry Flashcards
How can you find out the rate of a chemical reaction?
By monitoring the amount of reactants used up over time, you could also measure the rate of reaction by measuring the amount of products made up over time
What does the gradient of the line at any given time on the graph tell you?
The rate of reaction at that time.
What does it tell you when the line on the graph is very steep?
The faster the rate of reaction
What must particles do before they react?
They must collide, with a certain minimum amount of energy.
What is the activation energy of a reaction?
The minimum amount of energy that particles must have in order to react.
When does the rate of reaction increase?
If the surface area to volume ratio of any solid reactants is increased. This increases the frequency of collisions between reacting particles
What happens as the temperature increases?
The reactions happen more quickly
Why do reactions happen more quickly as the temperature increases?
Because particles collide more frequently and more energetically.
What does increasing the concentration of reactants in solutions do?
It increases the frequency of collisions between particles, and so increases the rate of reaction
What does increasing the pressure of reacting gases do?
It increases the frequency of collisions, and so increases the rate of reaction
What is a catalyst?
It is something that speeds up the rate of a chemical reaction, but is not used up itself during the reaction. It remains chemically unchanged.
When are catalysts used?
Whenever possible in industry to increase rates of reaction and reduce energy costs
What is a reversible reaction?
When the products can react together to make the original reactants again.
What type of reactions are there in reversible reactions?
One reaction is exothermic, the other is endothermic
In a reversible reaction, what happens to the energy?
The amount of energy transferred to the surroundings when the reactions go in one direction is exactly equal to the energy transferred back when the reaction goes in the opposite direction.
