Question 1 (True/False Worth 4 points) (03.06 LC) An instantaneous dipole occurs when a molecule's moving electrons are briefly
more concentrated in one place than another, causing the molecule to become temporarily polarized. True False
Question 2(Multiple Choice Worth 4 points) (03.06 LC) What type of intermolecular force occurs between all substances?
Covalent bonding
Hydrogen bonding
Ion-dipole force
London dispersion force
Question 3(Multiple Choice Worth 4 points) (03.06 MC) When comparing H2, NH3, O2, and CH4, which of the following statements is correct?
CH4 has the highest boiling point because it experiences dipole-dipole forces.
H2 has the strongest intermolecular forces because it has the lowest mass. NH3 has the highest boiling point because it experiences hydrogen bonding.
O2 has the strongest intermolecular force because it experiences London dispersion forces.
The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic Halogens Molecule Boiling Point
F2 −188 °C
Cl2 −34 °C
Br2 59 °C
I2 184 °C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increase down the group and this increases the strength of the intermolecular forces.
Question 5(Multiple Choice Worth 4 points) (03.06 MC) What is the strongest intermolecular force that occurs between molecules of CO2?
Dipole-dipole
Induced dipoles
Ionic bonding
London dispersion
1) True, when the electrons moving in a molecule or an atom move towards one end of the molecule or atom the other end has a small positive pole at that time and the end where electrons move has a small negative pole. So, a dipole is formed for that instant.
2) London dispersion force, remember from first part how an instantaneous dipole is formed. When a pole is formed at that instant the molecule in neighborhood can interact with the dipole that was formed. The dipole that was formed has a positive pole and a negative pole. If the neighboring molecule is present near positive pole it’s electrons will get attracted to the positive pole of the dipole. This interaction is called London dispersion force. Since every atom or molecule or ion in the universe has electrons, so there is development of instantaneous dipole in each of them and each one of them has London dispersion force acting on them.
3) one of the option is missing, none of these three is an answer.
4) The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
5) London dispersion forces which are always present.
London forces are weakest forces, if other forces would have been present then we would have ignored London forces but since no other forces are present, the only choice is London forces.
CO2 is a non polar molecule, it does not have permanent dipole moment. So there are no chances of dipole-dipole, CO2 doesn’t have a positive or negative charge so even not ionic bond.
