Chapter 8 Extent of chemical reactions Flashcards
Actual yield
The mass of product actually obtained in the chemical reaction. This will be less than or equal to the theoretical yield.
Closed system
A system which allows only energy to be exchanged with the surroundings.
Competing equilibria
Equilibria which have a common reactant; each equilibrium system can be regarded as competing for the reactant. The equilibrium system with the larger equilibrium constant has a significant effect on the position of equilibrium of the other reaction.
Dynamic equilibrium
A point in a chemical reaction at which the rate of the forward reaction is equal to the rate of the reverse reaction.
Open system
A system which allows matter and energy to be exchanged with the surroundings.
Equilibrium
In a chemical reaction system, equilibrium is reached when the quantities of reactants and products remain unchanged. The rates of the forward and reverse reactions are equal.
Equilibrium constant Kc
The value of the concentration fraction when equilibrium is reached, symbol Kc.
Equilibrium law
The equilibrium law as defined for a reversible reaction.
Equilibrium yield
The amount of product obtained when a chemical reaction reaches equilibrium
Extent of reaction
The relative amounts of products compared to reactants. The extent of the reaction is indicated by the value of the equilibrium constant
Heterogenous reactions
A chemical reaction in which at least two of the species are in a different state or phase
Homogenous reactions
A chemical reaction in which all the species are in the same state or phase
Irreversible reaction
A reaction in which significant reaction can occur in one direction only
Partial pressure
The pressure exerted by one component of a mixture of gases. The total pressure of a mixture of gases is equal to the sum of the individual partial pressures of each component in the mixture
Percentage yield
Percentage yield=(actual yield)/(theoretical yield)*100
Position of equilibrium
The relative amounts of reactants and products at equilibrium. The position of equilibrium varies depending on the extent of the reaction.
Rate of reaction
The change in concentration of a reactant or product per unit of time (usually one second).
Rate of reaction = (Change in Concentration)/Time
Reaction Quotient Qc/Concentration fraction
The ratio of concentration of products to reactants in a reversible reaction, as expressed in the equilibrium law.
Reversible reaction
A reaction in which significant reaction can occur in the reverse reaction as well as the forward direction. Products are present and can react with each other under suitable conditions.
Surroundings
The rest of the universe around a particular chemical reaction. The chemical reaction is the system. Energy moves between the system and the surroundings in endothermic and exothermic reactions.
System
In Chemistry, a system is a chemical reaction. A system operates within its surroundings. Energy moves between the two. You always consider energy as being absorbed or released from the perspective of the system. For example, energy is absorbed into the system from the surroundings, or energy is released by the system to the surroundings.
Theoretical yield
The mass that is expected for a particular product in a chemical reaction, based on the mass of limiting reactant used.
