Equilibrium. Equilibrium. The state where the concentrations of all reactants and products remain constant with time. Reactions are reversible. A + B C + D ( forward) C + D A + B (reverse) Forward and Reverse Rxns can be shown by double arrow. A + B C + D.
A + B C + D
Horse + Wrangler Mounted wrangler
A + B C
gaseous R dense P
aA + bB ⇄ cC + dD
So we call this K1
And K1= 1 = K2-1
cC + dD ⇄ aA + bB
So we call this K2
And K2= 1 = K1-1
4NH3(g) + 7O2(g) 4NO2(g) + 6H2O(g)
First write the equilibrium expression using no concentration values.
What is the value for K if the concentrations are as follows
NH3 1.0 M
O2 1.0 M
NO2 1.4 M
H2O 1.8 M
N2(g) + 3H2(g) 2NH3(g)
For: N2(g) + 3H2(g) 2NH3(g)
2NO(g) + Cl2(g) 2NOCl(g)
The following reaction has a K of 16. You are starting reaction with 9 O3 molecules and 12 CO molecules.
Find the amount of each species at equilibrium.
Q = K reaction is at equilibrium
Q > K too much products,
Q < K too much reactants,
For the synthesis of ammonia at 500°C, the equilibrium constant is 6.0 x 10-2. Predict the direction the system will shift to reach equilibrium in the following case:
In the gas phase, dinitrogen tetroxide
decomposes to gaseous nitrogen dioxide:
Consider an experiment in which gaseous N2O4 was placed in a flask and allowed to reach equilibrium at a T where KP = 0.133. At equilibrium, the pressure of N2O4 was found to
be 2.71 atm.
pressure of NO2.
At a certain temperature a 1.00 L flask initially contained 0.298 mol PCl3(g) and 8.70x10-3 mol PCl5(g). After the system had reached equilibrium, 2.00x10-3 mol Cl2(g) was found in the flask.
PCl5(g) PCl3(g) + Cl2(g)
Calculate the equilibrium concentrations of all the species and the value of K.
At 35°C, K=1.6x10-5 for the reaction 2NOCl(g) ⇄ 2NO(g) + Cl2(g)
Calculate the concentration of all species at equilibrium for the following mixtures
2.0 mol NOCl in 2.0 L flask
1.0 mol NOCl and 1.0 mol NO in 1.0 L flask
2.0 mol NO and 1.0 mol Cl2 in 1.0 L flask
Ex: N2 + 3H2 2NH3
Ex: NaCl(s) Na+(aq) + Cl-(aq)
Ksp = [Na+][Cl-]
(remember… solids are 1)
Process used to separate a solution containing different ions using solubilities
A solution of 1.0x10-4 M Cu+ and 2.0x10-3 M Pb2+. If I- is gradually added, which will precipitate out first, CuI or PbI2?
a. HF(aq) and NaF (F- in common)
b. HF(aq) H+(aq) + F-(aq) Excess F- added by NaF
a. NH4OH and NH4Cl (NH4+ in common)
b. NH3(aq) + H2O(l) NH4 +(aq) + OH-(aq)