What's the symbol?
Name the symbol (H+, HA, BH+, etc.) for the following compounds:
HCl
LiOH
HClO
NH3
H+
OH-
HA
B
What's left and which equation do we use to solve for pH?
3 moles HBr mixed with 1 mole NaOH
2 moles strong acid (H+)
Use strong acid formula [H+] = Ca
What's the pOH of a solution with 1x10-3 M H+ concentration?
pOH = 11
What is the approximate heat of vaporization of water? Is it a positive or negative value? Why?
About 40 kJ/mole
positive
heat is being added to the system
Which of the following factors affects the equilibrium constant K? Choose all that apply.
concentration of reactants
pressure
temperature
presence of catalyst
temperature only
Name the symbol (H+, HA, BH+, etc.) for the following compounds:
ammonium nitrate
potassium formate
barium hydroxide
BH+
A-
OH-
What's left and which equation do we use to solve for pH?
2 moles HClO4 mixed with 2 moles acetic acid
2 moles strong acid, 2 moles weak acid (no neutralization occurs)
Use strong acid equation [H+] = Ca
What is the approximate pH of 1x10-8 M HClO3?
The pH would be a little less than 7.
Little bubbles form when you heat water and fish swim to the poles when ocean waters warm.
What is the physical process associated with these phenomena, is it exo or endothermic and what happens when T increases?
O2(g) <--> O2(aq)
It is exothermic so when the temperature increases, the process shifts left and there is less oxygen in the water.
What do the initials RICE stand for and which of these initials must ALWAYS be stoichiometrically correct?
Reaction
Initial
Change
Equilbrium
C must be stiochiometrically correct
Name the symbol for the following compounds:
hydronium ion
potassium chloride
hypochlorous acid
dimethylamine
H+
neutral
HA
B
What's left and which equation do we use to solve for pH?
2 moles HNO3 mixed with 2 moles ammonia.
2 moles weak acid
Use weak acid formula [H+] = (KaCa)1/2
What's the pH of a 0.01 M NH4+ solution if the Kb for NH3 is 1x10-5?
pH = 5.5
What is the vapor pressure of a system with a 3 to 1 mole ratio of water and ethanol at 25oC?
(At 25oC vapor pressure of pure water is 20 torr and the vapor pressure of pure ethanol is 40 torr).
25 torr
For the reaction
3H2 + N2 ⇌ 2NH3
If 2 atm of each compound are initially added to the system, what is Q?
If K = 10, does the reaction shift left or right?
Q=0.25
Q=[NH3]2/[H2]3[N2]=22/(23*2)=0.25
Q < K so reaction shifts right.
Name the symbol(s) for the following compounds
NaH2PO4
Mg(OH)2
ammonium acetate
NaHSO3
(don't forget the polyprotic symbols like H2A, HA-, A=, etc.) :
H2A-
B
BH+ and A-
HA-
What's left and which equation do we use to solve for pH?
2 moles HI mixed with 3 moles ammonia
2 moles weak acid, 1 mole weak base
Use buffer equation [H+] = Ka(Ca/Cb)
What's the pH of 0.023M NaH2AsO4 if pKa values are 4, 8 and 11?
9.5
Amphiprotic. The concentration doesn't matter.
What would you predict as the signs for a salt dissolving exothermically in water?
Sign of crystal lattice energy
Sign of heat of hydration
Sign for heat of solution
Sign for entropy of solution
Sign for free energy of solution
Sign of crystal lattice energy +
Sign of heat of hydration -
Sign for heat of solution -
Sign for entropy of solution +
Sign for free energy of solution -
What is the molar solubility of
AgCl with a Ksp of 10-10
and
MgF2 with a molar solubility of 4 x 10-12
Which of the four ions (Mg+2, F-, Ag+, Cl-) is in highest concentration in water?
AgCl molar solubility is 10-5M
MgF2 molar solubility is 10-4M
F- is most soluble (twice as concentrated as Mg+2 because there are two F- for every Mg+2.)
Name all the strong acids and bases!
Strong acids: hydrochloric acid HCl, hydrobromic HBr, hydroiodic HI, nitric HNO3, sulfuric H2SO4, perchloric HClO4, chloric HClO3
Strong bases: lithium hydroxide LiOH, sodium hydroxide NaOH, potassium hydroxide KOH, rubidium hydroxide RbOH, cesium hydroxide CsOH, calcium hydroxide Ca(OH)2, strontium hydroxide Sr(OH)2, barium hydroxide Ba(OH)2
What's left and which equation do we use to solve for pH?
2 moles HCl mixed with 1 mole LiOH mixed with 2 moles (CH3)2NH
1 mole weak acid, 1 mole weak base
Use buffer equation [H+]=Ka(Ca/Cb)
What's the pH after 1 mole of NaOH is added to 2 moles of H3PO4 in a 1 liter container?
The pK values for H3PO4 are 3, 7 and 11.
pH = 3
This is a 1:1 buffer solution after the first mole of protons is removed from H3PO4 leaving H3PO4 and H2PO4-.
Given Kf=2 K/m and Kb=0.5 K/m for water, what would be the new temperature range for a 2 molal solution of CaCl2?
Freezing point would be 286 K.
ΔTb=iKbm=3 x 2 x .5 = 3
ΔTf=iKfm=3 x 2 x 2 = 12
New range is 115o
from -12oC to 103oC.
0.1 M NaOH is added to a saturated solution of Ca(OH)2. What is the new molar solubility of Ca2+?
Ksp=2x10-12 for Ca(OH)2.
You can assume that OH- from Ca(OH)2 is negligible compared to OH- from NaOH.
[Ca2+] = 2x10-10
Ksp=[Ca2+][OH-]2
[Ca2+]=Ksp/[OH-]2=2x10-12/(0.1+2x)2
2x << 0.1M OH- so
[Ca2+]=Ksp/[OH-]2=2x10-12/(0.1)2 = 2 x 10-10.