6 - The rate and extent of chemical change Flashcards
How can you work out the rate of a reaction?
Time taken
What are the unit(s) for rate of reaction?
g/s or cm3/s or mol/s
How do you read the rate of reaction off a graph at a specific time?
Calculate the gradient of a tangent to the curve
What are the factors affecting the rate of a chemical reaction?
Concentrations of reactions Pressure of reacting gases Surface area of solid reactants Temperature Presence of catalysts
Explain collision theory
Collision theory is the theory that says that reactions can only occur when particle collide, and that therefore the way that factors increase the rate of reaction is down to them increasing the frequency of collisions
Define a catalyst
A substance which changes the rate of a reaction without being used up
What are biological catalysts called?
Enzymes
How do catalysts work?
They work by prviding a different pathway for the reaction that has a lower activation energy
What is a reversible reaction?
A reaction in which the products can react to produce the original reactants
What is equilibrium
Equilibrium is when the forward and backward reaction occur at the same rate in a closed system
What happens when you change the conditions of a system at equilibrium?
The system responds to counteract the change (this is Le Chatelier’s Principle
What happens to the equilibrium when the concentration of a reactant is increased?
More products will be formed until equilibrium is reached again.
What happens to the equilibrium when the concentration of a product is decreased?
More reactants will react until equilibrium is reached again.
What happens to the equilibrium when the temperature is increased?
The relative amount of products for the endothermic reaction increases, and the amount of products for the exothermic reaction decreases
Which side of the reaction does increasing temperature benefit?
The endothermic side
