Valence Bonding, Hybridization, and Molecular Orbital Theory
Draw the hybrid orbital diagram for formaldehyde (H2C=O)
Draw correct diagram on board (sp2 hybridized with a double bond)
What state of matter has a rigid shape and a fixed volume?
Solid
What does a plateau represent on a heating curve represent? What about a sloped line?
Slope: A temperature change and change in state
How many grams of NaCl are required to make 500 mL of a 0.250 M NaCl solution?
7.31 g NaCl
Determine ΔH lattice for NaCl if the ΔH solution (NaCl) = +10.5 kJ/mol and the ΔH hydration (NaCl) = -760 kJ/mol.
770.5 kJ/mol
For the molecule, determine the hybridization around the central atoms.
H
|
H – C – C 三 N:
|
H
CH3 - sp3
C三N - sp
三 N: - sp2
What is the strongest intermolecular force? The weakest?
Ion-Ion (strongest), Dispersion (weakest)
What is a triple point?
Where a substance is existing as a solid, liquid, and gas simultaneously (all three states exist)
At 60°C, the solubility of NaNO₃ is 85 g per 100 g of water.
Identify the following solutions as saturated, unsaturated, or supersaturated: 130 g NaNO₃ added to 100 g of water,
170 g NaNO₃ added to 200 g of water,
40 g NaNO₃ added to 100 g of water
Supersaturated, saturated, unsaturated
Determine the solubility of O₂ in water at 30°C if the pressure of O₂ is 2.8 atm. The Henry's law constant for oxygen in water at this temperature is 1.3 × 10⁻³ M/atm.
0.00364 M
How many of the following molecules have a central atom with sp hybridization?
HCN
CO₂
BF₃
2 (HCN and CO2)
Place the following compounds in order of increasing strength of intermolecular forces:
C2H5OH (ethanol)
CH3OH (methanol)
CH4 (methane)
3, 2, 1
Label A-G on the phase diagram provided
*pull up image
A: Fusion curve
B: Sublimation curve
C: Solid
D: Liquid
E: Gas
F: Triple point
G: Critial point
Determine the freezing point depression of a solution that contains 40.0 g of urea (NH₂CONH₂, molar mass = 60.06 g/mol) in 500 mL of water. Use Kf = 1.86°C/m for water.
2.48°C
How many moles of NaCl is contained in 120.0 g of a 15.8% by mass solution of NaCl in water?
0.324 moles
What is the bond order of the ion O₂⁻? Is it paramagnetic or diamagnetic?
3/2, paramagnetic
Which of the following compounds would have the highest boiling point?
A. C6H14 (hexane)
B. C4H10 (butane)
C. C3H8 (propane)
D. C5H12 (pentane)
E. CH3OH (methanol)
E, methanol
Calculate the vapor pressure in torr of a substance at 29.0°C if its vapor pressure is 0.487 atm at 31.0°C and its ΔHvap is 45.0 kJ/mol.
329 torr
The vapor pressure of ethanol at 25 °C is 44.0 torr. If 0.80 g of ethanol is enclosed in a 4.0 L container, what is the mass of the liquid?
0.36 g
Calculate the molality of a solution formed by dissolving 50.0 g of KNO₃ in 750.0 g of water.
0.659 mol/kg
For the molecule SF₄Cl₂:
Draw the electron dot (Lewis) structure.
Determine the electron pair geometry around the central atom.
Determine the molecular geometry (shape).
Identify the hybridization of the central atom.
Determine the polarity of each bond (use electronegativities: S = 2.5, F = 4.0, Cl = 3.0).
Determine the overall polarity of the molecule.
1. draw on board
2. Octahedral
3. Octahedral
4. sp3d2
5. All bonds are polar
6. Polar molecule
Identify the type of solid for SiO2 (silicon dioxide):
A. Metallic atomic solid
B. Ionic solid
C. Nonbonding atomic solid
D. Molecular solid
E. Networking atomic solid
E, network atomic solid
How much energy (in kJ) is required to vaporize 125.0 mL of methanol (CH₃OH) at its boiling point?
Density of methanol = 0.7918 g/mL
Molar mass of methanol = 32.05 g/mol
ΔHvap = 35.20 kJ/mol
108.7 kJ
A solution is prepared from 5.00 g of NaCl and 50.00 g of H₂O. The vapor pressure of water above this solution is 0.3550 atm at the given temperature. The vapor pressure of pure water at this given temperature is 0.3725 atm. Find the value of the van't Hoff factor (i) for sodium chloride in this solution.
i = 1.60
A solution is prepared by dissolving 24.5 g of glucose (C₆H₁₂O₆) in 350 g of water. Determine the mole fraction of glucose if the final volume of the solution is 375 mL.
0.00696