Acids and Bases
Is HClO4 a strong acid, weak acid, strong base, or weak base?
What is a strong acid?
Does changing concentration impact the value of K?
What is it no?
The London (dispersion) forces are weakest for which of the following gases under the same conditions of temperature and pressure?
A H2
B O2
C Xe
D F2
E N2
What is H2?
If you have -∆S and -∆H, what is an appropriate ∆G prediction?
What is ∆G is - at low temperatures?
Ascorbic acid, H2C6H6O6(s), is a diprotic acid with K1 = 7.9 x 10-5 and K2 = 1.6 x 10-12. In a 0.005 M aqueous solution of ascorbic acid, which of the following species is present in the lowest concentration?
a.H3O+(aq)
b.C6H6O62-(aq)
c.H2C6H6O6(aq)
d.HC6H6O6-(aq)
What is C6H6O62-(aq)?
2 NO(g) + O2(g) <-> 2 NO2(g) ΔH < 0
Which of the following changes alone would cause a decrease in the value of Keq for the reaction represented above?
a. Decreasing the temperature
b. Increasing the temperature
c. Decreasing the volume of the reaction vessel
d. Adding a catalyst
What is increasing the temperature?
The electron cloud of HF is smaller than that of F2 , however, HF has a much higher boiling point than has F2 . Which of the following explains how the dispersion-force model of intermolecular attraction does not account for the unusually high boiling point of HF ?
A F2 is soluble in water, whereas HF is insoluble in water.
B The F2 molecule has a greater mass than the HF molecule has.
C Liquid F2 has weak dispersion force attractions between its molecules, whereas liquid HF has strong ionic interactions between H+ and F- ions.
D Liquid F2 has weak dispersion force attractions between its molecules, whereas liquid HF has both weak dispersion force attractions and hydrogen bonding interactions between its molecules.
What is D?
In an electrolytic cell, what type of charge do the anode and the cathode have?
What is the anode is positively charged and the cathode is negatively charged?
Which of the following mixtures would be considered a buffer?
a. 0.10 M HCl + 0.10 M NaCl
b. 0.10 M HF + 0.10 M NaF
c. 0.10 M HBr + 0.10 M NaBr
d. 0.10 M HClO2 + 0.10 M NaCl
What is 0.10 M HF + 0.10 M NaF?
Calculate the equilibrium constant K for the following equilibrium
3 F2(g) + Cl2(g) <-> 2 ClF3(g)
with the following equilibrium concentrations:
[F2]= 2.0 M; [Cl2] = 2.5 M; [ClF3] = 3.0 M
What is 0.45?
Which of the following could be the identity of a white crystalline solid that exhibits the following properties? • It melts at 320°C.
• It does not conduct electricity as a solid.
• It conducts electricity in an aqueous solution.
A C6H12O6(s)
B NaOH(s)
C SiO2(s)
D Cu(s)
What is NaOH?
Which of the following best accounts for the fact that a galvanic cell based on the reaction represented below will generate electricity?
Cl2(g) + 2 I-(aq) -> 2 Cl- (aq) + I2(aq)
A Cl2 can easily lose two electrons.
B Cl2 is a stronger oxidizing agent than I2.
C I atoms have more electrons than do atoms of Cl.
D I- is a more stable species than I2.
E I2(s) is more soluble than Cl2(g).
What is B, Cl2 is a stronger oxidizing agent?
A 0.20–molar solution of a weak monoprotic acid, HA, has a pH of 3.00. The ionization constant of this acid is:
a. 5.0x10-7
b. 2.0x10-7
c. 5.0x10-6
d. 5.0x10-3
What is 5.0x10-6?
PCl3(g) + Cl2(g) <-> PCl5(g) + energy
Some PCl3 and Cl2 are mixed in a container at 200oC and the system reaches equilibrium according to the equation above. Which of the following causes an increase in the number of moles of PCl5 present at equilibrium?
a. Decreasing the volume of the container
b. Raising the temperature
c. Adding a mole of He gas at constant volume
d. Increasing the volume of the container
Decreasing the volume of the container
At room temperature I2(s) is a molecular solid. Which of the following provides a characteristic of I2(s) with a correct explanation?
A It has a high melting point because it has weak intermolecular forces.
B It is hard because it forms a three dimensional covalent network.
C It is not a good conductor of electricity because its valence electrons are localized in bonding and nonbonding pairs.
D It is very soluble in water because its molecules are polar.
What is C?
H2Se(g) + 4 O2F2(g) --> SeF6(g) + 2 HF(g) + 4 O2(g)
Which of the following is true regarding the reaction represented above?
a. The oxidation number of O does not change.
b. The oxidation number of H changes from -1 to +1.
c. The oxidation number of F changes from +1 to -1.
d. The oxidation number of Se changes from -2 to +6.
What is D?
If the acid dissociation constant, Ka, for an acid HA is 8x10-4 at 25oC, what percent of the acid is dissociated in a 0.50–molar solution of HA at 25oC?
a. 0.08%
b. 4%
c. 1%
d. 2%
What is 4%
CuO(s) + H2(g) <-> Cu(s) + H2O(g) ∆H = –2.0 kJ
When the substances in the equation above are at equilibrium at pressure P and temperature T, the equilibrium can be shifted to favor the products by
a. increasing the pressure by means of a moving piston at constant T
b. increasing the pressure by adding an inert gas such as nitrogen
c. decreasing the temperature
d. allowing some gases to escape at constant P and T
What is decreasing the temperature?
A gas mixture at 0°C and 1.0 atm contains 0.010 mol of H2, 0.015 mol of O2, and 0.025 mol of N2. Assuming ideal behavior, what is the partial pressure of hydrogen gas (H2) in the mixture?
What is 0.20 atm?
Calculate ∆E for the system in which 16 J of work is done on a gas by the surroundings and the gas absorbs 51 J of heat?
a. -67 J
b. -35 J
c. +35 J
d. +67 J
What is +67 J?