Module 5- Static and Dynamic Equilibrium Flashcards
Closed system
A system that exchanges only energy with its surroundings, not matter. For e.g., saucepan of boiling water with lid on, saturated sugar solution.
Dynamic equilibrium
Occurs when the rate of the forward and reverse reaction are equal and not zero, so there is not net change. The reaction never reaches completion. Occurs only in a closed system with a reversible reaction. At an atomic level, bonds are constantly being broken and formed as the reactants are continually forming products and the products are continually forming reactants.
Enthalpy (H)
A measure of the total chemical energy possessed by a substance or group of substances. Measured in kJ/mol.
Entropy
A measure of disorder in a system. Measured in J/K/mol.
Irreversible reaction
A reaction that occurs in one direction and continues until one of the reactants is used up. These reactions go to completion.
Isolated system
A system that doesn’t exchange energy or matter with its surroundings.
Open system
A system that freely exchanges matter and energy with its surroundings. For example, saucepan of boiling water, combustion of wood, magnesium and acid.
Reversible reaction
A reaction that is able to go backwards depending on the prevailing conditions. Reactants can form products and products can form reactants. Reversible reactions always reach chemical equilibrium.
Spontaneous process
Favours the products under the conditions in which the reaction is occurring.
Static equilibrium
Occurs when the rate of the forward reaction in an irreversible reaction is equal to zero. The reaction has reached completion. At the atomic level, the reactions are no longer forming products, i.e., no chemical changes. Occurs in a closed and open system.
Surroundings
Everything in the universe that is not part of the system.
System
The part of the universe that is the focus of a thermodynamic study.
Universe
System+surroundings
