Chemical Equilibrium Flashcards
Catalyst
A substance that increases the rate of a reaction without being changed in chemical composition or amount. They work by providing an alternative reaction pathway with a lower activation energy
Closed system
A system where there is only heat exchange occurring between the system and its surroundings. No matter can enter or exit the system
Dynamic equilibrium
Dynamic equilibrium is reached when the rate of the forward reaction of a reversible reaction equals the rate of the backwards reaction. The concentrations of the reactants and products remains constant
Effect of changing concentration on equilibrium
If the concentration of a reactant increases, more products will be formed to re-establish the equilibrium
Effect of changing the pressure on equilibrium
If pressure is increased, the position of the equilibrium shifts towards the side with the fewest number of molecules. If the pressure is decreased, the position of the equilibrium shifts towards the side with the greatest number of molecules
Effect of changing temperature on equilibrium
If the temperature of a system in equilibrium is increased, there will be an increase in the relative amount of products for an endothermic reaction and a decrease for an exothermic reaction
Equilibrium constant (Kc)
A value that expresses the relationship between the concentration of products and reactants present at equilibrium in a reversible reaction
Heterogeneous system
A system where not all chemicals are in the same phase
Homogeneous system
A system where all the chemicals are in the same phase
Le Chatelier’s principle
If a reaction at equilibrium is subjected to a change in concentration, temperature or pressure, the position of equilibrium will move to counteract that change
Reversible reaction
Reactions in which the products from the reaction can react together to form the original reactants. The direction of reversible reactions can be changed by changing the conditions
