Advanced Theories of Covalent Bonding
What would be the bond order of the hypothetical molecule Ar₂?
0 (zero) It will have the same number of bonding and anti-bonding electrons hence bond order =(Nb-Nab)/2 bond order =0 Such molecules do not exist.
What is the bond order of H₂⁺?
0.5 Count the number of valence electrons in each atom and remember to remove an electron for the positive charge.. Then draw a molecular orbital energy diagram for this molecule to count the number of bonding and antibonding electrons to calculate bond order.
The molecular orbital energy diagram for F₂ is shown below. Based on this diagram, what is the bond order of F₂?
1 Count the number of bonding and antibonding electrons and calculate the bond order. Sample: BO= 12 (10−8) =1
Convert a pressure of 17.45 psi to atm.
1.187 atm
At STP, 5.00 mol of gas occupies approximately what volume in liters?
112L .The ideal gas law can be used to calculate the volume. Standard temperature and pressure is 0° C (273.15 K) and 1 atm.
Convert 2.70 atm to Torr
2050 torr
The molecular orbital energy diagram for N₂ is shown below. Based on this diagram, what is the bond order of N₂?A) 1B) 1.5C) 2.5D) 3E) 0
3 Count the number of bonding and antibonding electrons and calculate the bond order. Sample: BO=12 (10−4)=3
Which is NOT a property of an ideal gas? A) Consists of point particles B) Can pass through walls C) There are no attractive/repulsive forces D) All of the above are properties of ideal gases E) None of the above are properties of ideal gases
B) Can pass through walls An ideal gas consists of point particles and has no attractive or repulsive forces. It cannot pass through walls.
Which of the following molecules is paramagnetic according to molecular orbital theory? A) H₂ B) B₂ C) F₂ D) N₂
B2 Draw the MO diagram for this molecule, and then consider that paramagnetic molecules will have unpaired electrons. B₂ has unpaired electrons and is paramagnetic.
A 5.0 L chamber contains equal pressures of H₂ and N₂ at 25 °C. Which of these gases contains a larger number of molecules?
Both have equal numbers of moles. The number of moles would be the same under the same pressure, volume and temperature.
That a gas increases in pressure as its volume decreases is a statement of
Boyle's Law states that PV equals a constant. Therefore the statement that a gas increases in pressure as its volume decreases is another way of stating Boyle's Law.
Which of the following molecules has a bond order of 1.5 according to molecular orbital theory?
B₂⁻ Draw the MO diagram for all of the molecules, count the number of bonding and antibonding electrons. For example, this is the calculation for B₂⁻. BO=12(numberofbondingelectrons−numberofantibondingelectrons)BO=12(numberofbondingelectrons−numberofantibondingelectrons)BO=12(5−2)=1.5
Which of the following molecules is diamagnetic according to molecular orbital theory?
CN⁻ Draw the MO diagram for each molecule, and then consider that diamagnetic molecules will have no unpaired electrons. Only CN⁻ has no unpaired electrons.
According to molecular orbital theory, place the following molecules in order of increasing bond length: CN, CN⁺, and CN⁻.
CN⁻ < CN < CN⁺ Higher bond orders have higher stabilities and shorter bond lengths, so CN⁻ < CN < CN⁺ .
What is the LUMO of the Li₂ molecule?
D) 2σ* Draw a molecular orbital diagram for the Li₂ molecule. The LUMO is the lowest unoccupied molecular orbital, which is the 2σ* orbital.
At 25.0° C, a 10.00 L vessel is filled with 7.00 atm of Gas A and 5.89 atm of Gas B. What is the mole fraction of Gas B?
Gas B 0.457 Gas A 0.543 The mole fraction can be found by dividing the pressure of Gas B by the total pressure.
Which of the following molecules is considered least stable according to molecular orbital theory?
He₂ As with H2+, the He2+ ion should be stable, but the He-He bond should be weaker and longer than in H2. In fact, the He2+ ion can be prepared, and its properties are consistent with our predictions
Adding electrons to bonding molecular orbitals will:
Increase the bond order -- If you add electrons to the bonding molecular orbital, you increase the strength of the bond. Stronger bonds are associated with higher bond orders, so the bond order will not remain the same.
Which of the following molecules has a bond order of 2.5 according to molecular orbital theory?
NO Draw the MO diagram for all of the molecules, count the number of bonding and antibonding electrons. For example, this is the calculation for NO.
What is Standard Temperature and Pressure (STP)?
STP is defined as 273.15 K and 1.00 atm.
If the pressure on a movable piston of a closed container is doubled, what will happen?
Temperature will increase and volume will decrease, but the specific amount of each cannot be determined with the given information. Correct!
If a sealed, rigid container's pressure is doubled, what will happen to temperature?
The temperature will increase by a factor of 2
Complete the MO diagram (below) to determine if BO⁻ is paramagnetic or diamagnetic.
diamagnetic BO⁻ is diamagnetic. BO⁻ has 10 electrons in the valence shell. There are no unpaired electrons in this ion.
