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Intermolecular Forces Summary, Worksheet, and Key

Summary of Non-Covalent : Attractive Force Between:

Oxygen

or

Hydrogen Bonding H Lone Pair on:

(intermolecular) O or N or F or

Fluorine

Dipole- (intermolecular) Polar Polar Molecule Molecule

London Forces Any Any (intermolecular) Molecule Molecule

Positive or molecule

with a positive formal

charge Polar

Molecule Ion-Dipole or

Negative ion or molecule

with a negative formal

charge Polar

Molecule

Positive Ion or molecule with a positive formal charge Salt Bridge Negative Ion or molecule with a negative formal charge

Problems:

1) Name the dominant (strongest) in the following pairs:

Compound Dominant Force (Strongest Possible Force) Methane and Methane (CH4)

Ethanol and Ethanol

Water and

NH3 and NH3

Cyclohexanone and Cyclohexanone

Cyclohexanol and Cyclohexanol

HCl and HCl

CO2 and CO2

CCl4 and CCl4

CH2Cl2 and CH2Cl2

2) If the pairs of substances listed below were mixed together, list the non- covalent interaction(s) that are involved.

Choices:

(A) Bonding

(B) Dipole-Dipole

(C) London Forces (induced dipole)

(D) Ion-Dipole

(E) Salt Bridges (ionic forces)

Compound Pairs List of Non-covalent Interactions NH3 and H2O

2+ Mg and H2O

Cl2 and H2

Acetic acid and H2O

Acetic Acid

SO2 and H2O

SO2 and H2S ethane (CH3CH3) and methane (CH4)

Key

1) Name the dominant (strongest) intermolecular force in the following pairs:

Compound Dominant Force Methane and Methane London Forces

Ethanol and Ethanol Hydrogen Bonding

Water and Water Hydrogen Bonding

NH3 and NH3 Hydrogen Bonding

Cyclohexanone and Cyclohexanone Dipole-Dipole

Cyclohexanol and Cyclohexanol Hydrogen Bonding

HCl and HCl Dipole-Dipole

CO2 and CO2 London Forces

CCl4 and CCl4 London Forces

CH2Cl2 and CH2Cl2 Dipole-Dipole

2) If the pairs of substances listed below were mixed together, list the intermolecular force(s) that are involved.

Choices:

(A) Hydrogen Bonding

(B) Standard Dipole-Dipole

(C) London Forces (induced dipole)

(D) Ion-Dipole

(E) Salt Bridges (ionic forces)

Compound Pairs List of Intermolecular Forces NH3 and H2O A, B, C

2+ Mg and H2O D

Cl2 and H2 C

Acetate ion and H2O A,B,C

Acetic Acid

SO2 and H2O A,B,C

SO2 and H2S B,C ethane (CH3CH3) and methane (CH4) C