Chapter 12
The lattice energy of KBr is +665 kJ/mol
The hydration energy of KBr is -657,000 J/mol
This is the enthalpy of solution for KBr in kJ/mol. (ignore sig-figs)
What is +8 kJ/mol?
When reactant species collide with both proper orientation and adequate energy, they combine to form an unstable species.
What is an activated complex or a transition state?
Given the two reactions shown with their equilibrium constants,
PCl3(g) + Cl2(g) --> PCl5(g) K1
2 NO(g) + Cl2(g) --> 2 NOCl(g) K2
What is the equilibrium constant for the reaction,
PCl5(g + 2 NO(g) --> PCl3(g) + 2 NOCl(g)
K2/K1
The pH of a solution is 3.54. This is the concentration of OH- ions.
3.46*10-11M
The requirement for a spontaneous chemical reaction is
deltaG < 0
A solution is 19.00% KBr by weight. This is the molality of this solution.
What is 1.971 mol/kg?
2NO(𝑔)+Cl2(𝑔)⟶2NOCl(𝑔)
When you double the concentration of nitrogen monoxide (all else equal), you observe the reaction rate quadruples.
This is the order of nitrogen monoxide in the rate law expression
What is second-order?
Using Le Châtelier's Principle, describe how we could maximize the amount of ammonia produced in
the Haber-Bosch process, by the reaction:
N2(g) + 3H2(g) --> 2NH3(g)
Remove ammonia from the reaction container, increase pressure, and look at enthalpy.
Name and explain the three acid/base theories.
Arrhenius, Bronsted, Lewis
Give three examples of an increase in entropy.
Multiple
In the lab, you add 15.72g compound A to 100g water and observe the freezing point decrease by 5.0°C. The Kf of water is 1.86°C/m. The compound is known to be either KBr, LiCl, NaCl, KI, or KF. Which compound is compound A?
What is NaCl?
CH3OH+CH3CH2OCOCH3⟶CH3OCOCH3+CH3CH2OH
The rate law for the reaction between methanol and ethyl acetate is, under certain conditions, determined to be:
rate=𝑘[CH3OH]
This is the order of reaction with respect to methanol and ethyl acetate, and this is the overall order of the reaction.
What is...
order wrt methanol: 1
order wrt ethyl acetate: 0
overall order: 1
Why don't the concentrations of pure solids and liquids appear in the equilibrium laws of chemical
reactions?
The concentration of pure solids and liquids is essentially constant. That is to say, the ratio of the
number of moles of the solid or liquid is in a fixed proportion to its volume. This means that, no matter
what the volume of a pure substance, its concentration is the same.
The powerplant explosion in Superior came close to spilling large amounts of HF into the environment. Would this be more or less harmful compared to if this were HCl?
What is more harmful?
Give three examples of an decrease in entropy
Multiple
This common vitamin is water-soluble.
What is Vitamin C?
For a first-order reaction, [A]0=1. After 20 seconds, [A]=0.1. Predict [A] after an additional 6 seconds.
What is 0.0501M?
Explain, in terms of Le Châtelier's Principle, why cold packs are used for treating injuries.
The body responds to injuries by repairing itself. This repair process produces energy, which is why the
areas around muscle injuries are warm. Since this repair is an exothermic process, adding cold to the
area draws heat away from the injury. The body will then supply more oxygen-rich blood to the injured
area, speeding up healing.
A solution is made by dissolving 15.00 grams of acetic acid and 3.25 grams of sodium acetate
in 500.00 mL of water. What is the pH of the solution? The Ka of acetic acid is 1.8 x 10-5.
3.94
The Ksp of iron(II) hydroxide, is 4.87 x 10-17. This is the molarity of iron (II) in solution.
What is 2.3*10-6 M.
This many mL of 0.10 M HCl must be added to 50 mL of 0.40 M HCl to give a final solution that has a molarity of 0.25 M.
What is 50mL?
Species that are produced in one step and consumed in a subsequent step.
What are Intermediates?
A chemical system is considered to have reached dynamic equilibrium when:
the rate of production of each of the products is equal to the rate of their consumption by
the reverse reaction.
The pKa of a weak acid is 6.50. What is the value of Ka for this acid?
3.2 × 10-7
1. Alkali metal (Group IA) compounds are ______.
2. Ammonium (NH4+) compounds are ______.
3. _______ (NO3-), chlorates (ClO3-), and perchlorates (ClO4-) are _______.
4. Most hydroxides (OH-) are _______.
1. soluble
2. soluble
3. nitrates, soluble
4. insoluble, alkali, slightly
5. soluble, Ag+, Hg+2, and Pb+2.
6. phosphates, insoluble
7. soluble, insoluble