N2O4 ââ 2NO2 Forward reaction rate law: rate = k1[N2O4]
Backward reaction rate law: k-1 [NO2]
If at equilibrium, the concentrations of the products and reactions do not chagne. For this to be true, what is true about the rates of the forwards and backwards reactions?
- The reactions happen at the same rate frrl = brrl K1/K-1 = frrl/brrl = Kc which is the equilibrium constant
Acidity is only 7 at room temperature
Equilibrium happens when the forward and backward reaction rates are equal to each other. This means that the concentrations of both products and reactants stay constant, but crucially both reactions continue to happen
Any general equilibrium can be written as
aA + bB ââ cC + dD
products over reactions in equilibrium rate law
A 0.5L glass container is charged with 45.0g of NO2 and 82.0g of Br2. Find the equilibrium concentrations of all the gasses
| I | 1.05M | 0 | |
|---|---|---|---|
| C | -x | +2x | |
| E | |||
| 0.120=(2x)^2/(3.00-2x)^2(1.03-x) |
3.00-2(.140)=2.72M [NO] [BR2] = 1.03-.14 = .89M [NoBr] = 2(.140) = .280M
If x is very tiny compared to your amount of starting material we can assume that the equilibrium amount is basically equal to the starting amount
5% rule: if x is 5% or less than our initial amount we ignore it
1.50 * 10^10=x(x/)/1-x x=1.23x10
5% rule, 1.50 x 10^-10=x^2/1
x=1.22x10^-5 M
x=0.167 M, nowhere near normal answer. Go back and get exact answer anyway
Kc = C^c d^d / A^a B^b = Kc/Keq
Constants are functions of temperature
If Kc >> 1 then All products A-âB If Kc << 1 then All reactants no reaction
Rate constant for forwards is larger than rate constant for backwards if Ae is bigger
Combining Equilibria
K2c1 = concH+F-/HF
Solids and liquids in equilibrium expressions
- Ammonium + water = ammonium + oh-
Kc = NH4 OH / NH3 H2O
water is a constant value of ~55.6 you can just multiply and absorb into the constant so you only have one thing on the bottom
Kp = pressure equilibrium constant Kp = Pso2 squared Po2/ Pso3 squared
2SO3 â> 2SO2 + O2
ICE Table for equilibrium?
Reaction Quotient
- We often want to know which direction a reaction is going to shift based on current conditions. To determine this we calculate