1-6: Equilibria And Redox Flashcards
(26 cards)
Define dynamic equilibrium
The rate of the forward reaction is equal to the rate of the reverse reaction
What is an essential condition for an equilibrium mixture?
Closed system where reactants and products cannot escape
State Le Chatelier’s principle
If a system at equilibrium is disturbed, the equilibrium moves in the direction that tends to reduce the disturbance
What effect would increasing the temperature have on the position of equilibrium?
Shifts in the endothermic direction
What effect would increasing the pressure have on the position of equilibrium?
Equilibrium shifts in the direction with fewer moles
What effect would the addition of a catalyst have on the position of equilibrium?
No effect, rate of forward and backward reaction increases equally
What condition affects the value of Kc?
Temperature
What is the Kc constant?
What is the equation for rate of reaction?
ROR = amount of reactants used or product formed/ time
What effect would increasing the concentration of the reactant have on the position of equilibrium?
Equilibrium shifts in the opposite direction to the reactants
What is the Kc equation?
Kc= (D)^d(E)^e
(A)^a(B)^b
Where lower case = moles and upper case = concentration (mol/dm^3)
What does 1/mol/dm^3 simplify to?
Mol^-1dm
What does Kc being greater than or less than 1 suggest to the position of equilibrium?
- > 1 = over to the right
- <1 = over to the left
What effect does decreasing the temperature on Kc in an endothermic reaction?
- decreases
- shift in exothermic direction (left)
- left <1
What effect does increasing the concentration/pressure of reactants have on the Kc constant?
No effect on th Kc constant, the concentrations of the other things will change to keep Lc the same since Kc is fixed at a given temperature
What is an oxidation number?
The number of electrons an atom uses to bond with any other atom
What is the oxidation state of an uncombined element
0
What is the oxidation number of oxygen in peroxides?
-1
Define oxidation in terms of electron transfer and oxidation number
Oxidation is loss of electrons and increase in oxidation number
Define reduction in terms of electron transfer and oxidation number
Reduction is gain of electrons and decrease in oxidation number
What is a redox reaction?
A reaction in which both reduction and oxidation takes place
What is the oxidation state of a metal?
0, uncombined element
How do high temperatures and pressures and the use of catalysts affect the cost and yield of a reaction?
- high temp: increases yield (depending on reaction) and cost therefore compromise temp used
- high pressure: increases yield (depending on reaction) and cost therefore compromise pressure used
- catalyst: has no effect on yield, allows lower temp to be used so lowers cost
What is partial pressure and how do you find it?
The pressure that a gas in the mixture would exert if it was in the container on its own
- subtract moles made from reactants moles to account for initial reaction
- fraction of gas over total gas x real pressure
