Ch. 9: Ideal Gas Law
What is the Ideal Gas Law equation? What does each variable stand for?
PV=nRT
pressure, volume, moles, gas constant, temperature
Describe each of the following IMFs:
- dispersion forces
- dipole forces
- Hydrogen bonding
dispersion forces = in everything
dipole forces = polar molecules
Hydrogen bonding = H connected to F, O, N (hydrogen on the "phone")
What equation should you use with dilution problems?
What does each variable stand for? What are their units?
M1V1 = M2V2
M = concentration (mol/L)
V = volume (L)
What does La Chatelier's principle say?
If you "disturb" a reaction at equilibrium, the reaction will shift to counteract that disturbance.
if the pH of a solution is 3, what is the pOH?
11
What is the gas constant, R? Include units with your answer.
0.08206 (L*atm)/(mol*K)
flat lines = phase change (melting, vaporization)
sloped lines = heating
A chemist prepares a solution of silver(I) nitrate (AgNO3) by measuring out 94.1μmol of silver(I) nitrate into a 250 mL volumetric flask and filling the flask to the mark with water.
Calculate the concentration in M of the chemist's silver(I) nitrate solution
3.76 x 10-4 M (mol/L)
How does the reaction rate change when we:
increase volume?
increase temperature?
increase volume = reaction rate decreases
increase temperature = reaction rate increases
What is the equation to find pH?
What is the equation to find pOH?
pH = -log[H+]
pOH = -log[OH-]
density = (P/RT)M
M = molar mass
What intermolecular forces are present in the following compounds:
Ar2
HClO
hydrogen chloride
ammonia
Ar2: dispersion only
HClO: dispersion, dipole-dipole, hydrogen bonding
hydrogen chloride: dispersion, dipole-dipole
ammonia: dispersion, dipole-dipole, hydrogen bonding
What is the better solvent for I2: H2O or CH3(CH2)4CH3?
What is the better solvent for NaCl: H2O or CH3(CH2)4CH3?
What is the better solvent for KCl: H2O or CCl4?
For I2: CH3(CH2)4CH3
For NaCl: H2O
For KCl: H2O
Write the equilibrium constant expression for the following reaction:
2 CuI(s) + I2(aq) → 2 Cu2+(aq) + 4 I-(aq)
don't include solids or liquids in K!
[I-]4[Cu2+]2 / [I2]
What is the conjugate base of H2O?
What is the conjugate acid of NH3?
conjugate base of H2O: OH-
conjugate acid of NH3: NH4+
What is the volume of 0.02134 mol of a gas at 1 atm of pressure and 39°C? Include units with your answer.
0.547 L
In each pair of compounds, which one has the higher boiling point?
CS2 vs. C2H4
GeH4 vs. PbH4
Ar vs. Ne
CS2
PbH4
Ar
A chemist makes 400. mL of working solution by adding distilled water to 250. mL of 0.365 M stock solution. What is the concentration of the chemist's working solution?
0.228 mol/L
What is the solubility expression (Ksp) for CuCO3?
Ksp = [Cu2+][CO32-]
What is the concentration of H3O+ of a solution with a pH of 4.57?
2.7 x 10-5 mol/L
You have a tank with some N2O and SF4 gas.
There is 6.54 g of N2O and 7.02 g of SF4. The tank is 5.00 L and 0.88°C.
What is the partial pressure of N2O? (in atm)
0.668 atm
Calculate the amount of heat needed to melt 32.4 g of acetic acid and bring it to a temperature of 109.8°C.
(The molar mass of acetic acid is 60.05 g/mol. The heat of fusion for acetic acid is 11.73 kJ/mol. The change in temp is 98 K. The specific heat capacity for acetic acid is 2.053 J/g*K.)
12.5 kJ
A chemistry student weighs out 0.0712 g of phosphoric acid (H3PO4) into 250 mL flask and dilutes to the mark with water. He plans to titrate the acid with 0.0600 M NaOH solution.
Calculate the volume of NaOH needed to reach the final equivalence point. The balanced equation is shown below:
H3PO4 + 3 OH- → PO43- + 3 H2O
36.3 mL or 0.0363 L
You have an endothermic reaction, shown below.
4 NO + 6 H2O → 4 NH3 + 5 O2
What direction will the reaction shift if we lower the temperature? What will happen to the pressure of O2?
shifts to the left
O2 pressure will go down.
A chemist dissolves 431 mg of HCl in 150 mL of solution. Calculate the pH of the solution.
(hint: the molar mass of HCl is 36.458 g/mol)
pH = 1.1034