Le Châtelier's Principle
Equilibrium Expressions
Calculations
Q versus K
Mrs . Latta
100
The direction of the equation shifts this way, when products are added to the equilibrium expression.
What is shift to the left? (towards reactants)
100
Define K and k
K = equilibrium expression
k = rate constant
100
An equilibrium mixture is analyzed and found to contain 0.62M N2, 0.50M H2, and 0.24M NH3. What is Kc for the reaction, N2(g) + 3H2(g) <--> 2NH3(g)
Kc= 0.74
100
If Q < K which direction will the reaction shift?
towards the products
100
How old is Mrs. Latta?
29
200
The direction of the equation shifts this way, when reactants are added to the equilibrium expression.
What is shifts right? (towards products)
200
The equilibrium constant used for identifying expressions with molar solutions.
Kc or Keq
200
N2(g) + 3 H2(g) <-> 2 NH3 (g) K = 2.5
Determine which direction a reaction will shift if
[N2] = 1.0 M, [H2] = 0.30 M, and [NH3] = 3.5 M
Q > K towards reactants
200
Expresses the relative ratio of products to reactants at a given instant. Uses the initial concentration not at equilibrium.
Reaction Quotient, Q
200
How old is Mr. Latta?
29
300
Speeds up the reaction but does not change the equilibrium constant.
A catalyst
300
NH4SH (s) --> NH3 (g) + H2S (g) Write the equilibrium expression.
Kc = [NH3] [H2S]
**solids not included in equilibrium expression
300
2 CH4(g) <-> C2H2 (g) + 3 H2 (g) Kc=0.154
Starts off with 4.00 M CH4, 2.00 M C2H2, and 3.00 M H2 which direction will the reactin progress to reach equilibrium?
Q > K, so a net reaction occurs towards the reactants.
300
The relation between Q and K when the system is at equilibrium.
Q=K
300
When is Mrs. Latta's birthday?
October 28th
400
N2 + 3 H2 ⇌ 2 NH3 ΔH = -92kJ
Equilibrium shifts in which direction when heat is added?
Left (reactants)
400
2SO2 (g) + O2 (g) --> 2SO3 (g)
Write the equilibrium expression for the reaction above.
K = [SO3]2 / [SO2]2 [O2]
400
At a given temperature, an equilibrium mixture of the reaction 2NO(g) + O2(g) <--> 2NO2(g) contains 0.090 moles NO, 0.120 moles of O2, and 0.060 moles of NO2 in a 3.00 liter container. The value of Kc is...
Kc= 11
400
The relation between Q and K where there are more products than reactants. Causes a shift to the left to compensate.
Q > K
400
Where is Mrs. Latta going for Spring Break?
Japan
500
N2 + 3 H2 ⇌ 2 NH3
Shifts the equilibrium system in which direction when pressure is increased? (assume all substances are gases)
right (products)
500
Write the equilibrium expression for the following reaction: 2 NO (g) + Cl2 (g) --> 2 NOCl (s)
1 / [NO]2[Cl2]
500
PCl3 + Cl2 <--> PCl5 [PCl3] is 0.5 M, [Cl2] is 0.07 M. If K = 96.2 what is [PCl5]?
[PCl5] = 3.4 M
500
H2(g) + I2(g) <-> 2 HI Kc= 50.5
Predict in which direction the reaction will proceed, if there is 2.0x10-2 mol of HI, 1.0x10-2 mol H2 and 3.0x10-2 mol I2 in a 2.0 L container.
Q < K shift towards products
500
What kind of dog does Mrs. Latta have?
Giant Schnauzer
