4.6🎀 Flashcards
How to do you calculate the rate of a reaction?
Amount of reactant used/time
What can quantity of reactant or product be measured in?
Mass in grams, or by volume in cm^3 or moles!
How do you work out the rate of a reaction graphically?
Draw a tangent at desired point. Then use the tangent to draw a triangle and from there work out gradient.
What are the factors that affect the rates of a reaction?
Concentration, pressure, surface area, temperature and catalysts
How do concentration, pressure and surface area affect the rates of chemical reactions?
More particles in a given volume which means collisions will occur more frequently. This means more particles reach the required activation energy and therefore the rate of the reaction is increased
How does temperature effect the rate of chemical reactions?
When temperature is increased, particles gain more kinetic energy and this means collisions will occur more frequently because they are moving faster and so more particles reach the required activation energy and the rate of reaction is increased.
How does a catalyst affect the rate of a reaction?
Catalysts are substances that speed up the rate of a reaction without being used up themselves. Catalysts decrease the activation energy by providing an alternative pathway for the chemical reaction.
What is the collision theory?
Explains how various factors affect the rates of reactions, according to this theory chemical reactions can only occur when the particles collide with each other with sufficient energy.
What is activation energy?
The minimum amount of energy that particles must have too react is called the activation energy
What is a reversible reaction?
The direction of a reaction can be changed by changing its conditions.
What symbol represents a reversible reaction?
(A forwards and backwards half arrow)
According to a reversible reaction, if a reaction is endothermic one way what is it in the other direction?
Exothermic reaction and the same amount of energy is transferred. (For one energy is lost and the other energy is gained)
What is a (dynamic) equilibrium
When reversible reactions occur in a closed system and the forwards and backwards reactions occur at the same rate - equilibrium is reached.
What is a closed system?
When a reaction isolated from its surroundings which prevents the reactants and products from escaping into the atmosphere
What does le chateliers principle state?
The relative amounts of all the reacting substances at equilibrium depend on the conditions of the reaction. If a system at equilibrium has a change made too it, the system responds to counteract that change.
