Equilbrium Constant for Homogeneous Systems PHYSICAL Flashcards
What does the equilbrium expression link?
Equilibrium constant to concentrations of reactants and products at equilibrium
What is taken into account for equilibrium expression?
Stoichiometry
What symbol is used for equilibrium constant involving concentrations?
Kc
What is the equilibrium expression for reaction aA + bB ⇌ cC + dD?
Kc = [C]ᶜ[D]ᵈ/[A]ᵃ[B]ᵇ
What are ignored in Kc equilbrium expressions?
Solids
What changes the Kc of a reaction?
Only temperature
What symbol is used for equilibrium constant involving partial pressures?
Kp
What is the equilibrium expression for Kp for reaction aA + bB ⇌ cC + dD?
Kp = pᶜC(g)eqm pᵈD(g)eqm / pᵃA(g)eqm pᵇB(g)eqm
What are ignored in Kc equilbrium expressions?
Solids and liquids
What changes the Kp of a reaction?
Only temperature
What is meant by partial pressure of a gas?
The pressure it exerts in a mixture of gases if it occupied the containenr on its own
What symbol is given to partial pressure?
p
What is Dalton’s Law?
The total pressure of a mixture of a gases is the sum of the partial pressures of each gas
What information is needed to find the partial pressure of a gas?
The total pressure in container
The mole fraction Kp
How is partial pressure calculated?
Total pressure x mole fraction
How is mole fraction calculated?
Number of moles of gas x / total number of moles of gas
What is found in each step of a Kp calculation?
Mole fractions of gases present
Parital pressures
Kp expression
Value of Kp
What does Le Chatelier’s principle say?
If a change is made to a system in dynamic equilibrium, the position of equilibrium moves to counteract change
What is Le Chatelier’s principle used to predict?
Changes to position of equilibrium when there is changes in temperature, pressure or concentration
How does the equilibrium shift when temperature is increased?
Moves in endothermic reaction to reverse change
How does the equilibrium shift when temperature is decreased?
Moves in exothermic reaction to reverse change
How does an equilibrium shift in endothermic reaction affect Kp?
The value of Kp will increases as ratio of [products] to [reactants] increases
How does an equilibrium shift in exothermic reaction affect Kp?
The value of Kp will decreases as ratio of [products] to [reactants] decreases
How does the equilibrium shift when pressure is increased?
Move in directions that produces smaller number of molecules of gas to reverse change
