1.7 Simple Equilibrium & Acid-base Equilibrium Flashcards
Why is equilibrium described as a dynamic state?
Because there is a constant change on a molecular level.
What is equilibrium?
A state of balance of a reversible reaction that has been left to carry on, where both reactions are happening at the same rate.
Give examples of large scale (macroscopic) properties that do not change during equilibrium?
Concentration, electrical conductivity, colour, pressure of gas, mass of solids
What are the features of an equilibrium state?
@ taking place in an isolated or closed system.
@ forward and reverse reactions take place at equal rate.
@ constant change on a molecular level, eg association and dissociation
@ macroscopic properties are constant
@ same position of equilibrium can be achieved from either direction under the same conditions
What happens to the concentrations of products and reactants as it reaches equilibrium in a closed system?
Concentration of reactants decrease until it reaches equilibrium and remains the same, but the concentration of the products increase until it reaches equilibrium and it stays the same
What is Le Chatalier’s Principle?
The idea that if any condition is changed to a system in equilibrium, it will try to reverse the effect by a chemical process
How can a forward reaction be promoted in terms of concentration?
By increasing the amount of a reactant, or by removing a product as it forms
How can the reverse reaction be promoted in terms of concentration?
When reactants are used up, the system will try to create more reactants by promoting the reverse reaction. Also, if the the product is allowed to build up, the system will, try to use up the products to form more reactants
What is meant by a reversible reaction?
A process that can proceed in either direction, where the reactants can form the products, and the products can form the reactants through the reverse reaction.
What are the 3 conditions that effect the position of equilibrium?
Concentration, pressure and temperature
How does changing the pressure affect the position of equilibrium?
If you increase the pressure of a system, the system will promote the reaction that forms the least amount of moles, in order to decrease pressure.
If pressure is decreased, the system will counteract but promoting the reaction that creates the most moles of gas, in order to increase pressure
How does temperature effect the position of equilibrium?
If the temperature is decreased, the system will promote the reaction that releases heat (exothermic) in order to increase temperature.
If the temperature is increased, the system will promote the endothermic reaction, to take away that excess heat
What effect does a catalyst have on a reversible reaction?
A catalyst increases the rate of both the forward and reverse reaction, so equilibrium is achieved sooner
What does a large Kc value indicate? >1
It shows that there is more product being formed than reactants, so equilibrium will lie to the right hand side
