Theories of Covalent Bonding (C11)
Equilibrium
Le chatelier's principle
Acid-Base Titrations
Misc
100
Let’s take HCN, what is the Lewis Structure, steric number and hybridization of the central atom
A:H-C≡N, 2, sp
100
Explain what it means for a reaction to be at equilibrium
The rate of the forward reaction and the reverse reaction are the same, meaning that the reactants will produce products at the same rate that products will produce reactants
100
The following reaction is exothermic: 3NO(g) ⇌ N2O(g) + NO2(g)
Predict the effect upon the amount of NO(g) for each of the following stresses:
N2O(g) is added to the equilibrium mixture
Increase
100
Calculate the pH in the titration of 25.0 mL of 0.100 M HCl by a 0.100 M solution of NaOH after the addition of 10.0 ml of NaOH
pH = 1.368
100
Calculate the pH of a 0.18 M NH3/0.20 M NH4Cl buffer
9.20
200
What is the difference between a sigma and a pi bond
A: end to end overlap, side to side overlap
200
Please write the formula for your reaction quotient(Q) and then describe what would happen if Q is less than K, Q is greater than K, and Q is equal to K
Reaction proceeds to the right, Reaction proceeds to the left, reaction is at equilibrium
200
The following reaction is exothermic: 3NO(g) ⇌ N2O(g) + NO2(g)
Predict the effect upon the amount of NO(g) for each of the following stresses:
The volume of the equilibrium mixture decreases
Decrease
200
Calculate the pH in the titration of 25.0 mL of 0.100 M HCl by a 0.100 M solution of NaOH after the addition of 35.0 ml of NaOH
pH = 12.22
200
What are the six strong acids, and what does it mean for an acid to be strong?
HCl, HBr, HI, H2SO4, HNO3, HClO4
300
Name two of the five rules regarding hybridization:
1) Hybridization does not occur in isolated atoms. It is
used only to explain the bonding scheme of a molecule.
2) Hybridization is the mixing of at least two non equiva-
lent atomic orbitals from the same atom. A hybrid or-
bital is, therefore, different in shape and orientation
from any of the original atomic orbitals.
3) The number of hybrid orbitals formed is equal to the
number of atomic orbitals that were mixed.
4) Hybridization requires energy to occur, but the energy
expenditure is more than compensated when the bonds
Form.
5) Covalent bonds in polyatomic molecules are the result
of hybrid atomic orbitals of the central atom overlapping
the (usually) hybridized atomic orbitals of the con-
stituent atoms (exception: H atoms, since they would
use unhybridized s orbitals to bond). Since the bonds
are due to the overlap of atomic orbitals, hybridization
is appropriate to valence bond theory.
300
The following equilibria have been studied at 2.30 * 102 C:
2NO(g) + O2(g) ⇌ 2NO2 (g)
In one experiment, the concentrations of the reacting species at equilibrium are found to be [NO] = 0.0452 M, [O2] = 0.127 M, and [NO2] = 15.5 M. Calculate the equilibrium constant K of the reaction at this temperature
K = 1.56 * 104
300
The following reaction is exothermic: 3NO(g) ⇌ N2O(g) + NO2(g)
Predict the effect upon the amount of NO(g) for each of the following stresses:
The temperature of the equilibrium mixture is decreased
Decrease
300
Calculate the pH in the titration of 25.0 mL of 0.100 M CH3COOH by a 0.100 M solution of NaOH after addition of 10.0 mL of NaOH
pH = 4.581
300
The observed osmotic pressure for a 0.100 M solution of Fe(NH34)2(SO4)2 at 25.0 C is 10.8 atm. Compare the expected and experimental values for i
i = 4.41 which is smaller than 5
400
Please draw the energy level diagram for O2 and O2 2- and identify the magnetic behavior
400
The reaction
2HI(g) ⇌ H2(g) + I2(g)
Has an equilibrium constant at 430 C of 0.0184. Suppose that a reaction vessel at 430 C contains these substances with an initial partial pressure
PH2 = 0.359 atm
PI2 = 0.239 atm
PHI = 1.29 atm
What will the partial pressures be at equilibrium?
PHI = 1.47 atm
PH2 = 0.268 atm
PI2 = 0.148 atm
400
The following reaction is exothermic: 3NO(g) ⇌ N2O(g) + NO2(g)
Predict the effect upon the amount of NO(g) for each of the following stresses:
Gaseous argon(which does not react) is added to the equilibrium mixture
No effect
400
Calculate the pH in the titration of 25.0 mL of 0.100 M CH3COOH by a 0.100 M solution of NaOH after addition of 25.0 mL of NaOH
pH = 8.728
400
Will a precipitate form when 0.100 L of 3.0 * 10-3 M Sr(NO3)2 is added to 0.400 L of 5.0 * 10-3 M Na2SO4(Hint: THe Ksp for SrSO4 is 3.44 * 10-7)
A precipitate will form since Q is greater than Ksp
500
What is the difference between how the sigma and pi orbitals are filled in lighter vs. heavier diatomics
Heavier second period homonuclear diatomics O2, F2 have nuclear charges that are large enough to keep the sigma 2s electrons close to the nuclei where they interact less with the sigma 2p allowing the sigma 2p to become occupied before the pi2p(sigma 2p are lower in energy than the pi 2p)
500
Please explain the common ion effect and solve this problem. Compare the pH of a solution that is 0.30 M in formic acid(HCOOH) and 0.52 M in potassium formate (HCOOK) to that of a solution that is 0.30 M formic acid solution (approximate)
3.99 vs. 2.14
500
The following reaction is exothermic: 3NO(g) ⇌ N2O(g) + NO2(g)
Predict the effect upon the amount of NO(g) for each of the following stresses:
Gaseous argon is added to the equilibrium mixture while keeping the total gas pressure constant
Increase
500
Calculate the pH in the titration of 25.0 mL of 0.100 M CH3COOH by a 0.100 M solution of NaOH after addition of 35.0 mL of NaOH
pH = 12.22
500
Calculate the molarity, molality, and mole fraction of HCl in an aqueous solution which is 38.0% by mass HCl, given that the density of the solution is 1.19 g/cm3
Molarity:12.4, molality = 16.8, Mole fraction = 0.232