9.5 Intermolecular Forces

Read the information in the image.

What are the forces called that hold molecules together?

• Intermolecular forces

• Intramolecular forces

• chemical forces

• bonds

• physical forces

What is represented inside each box?

• H2O molecule

• H atom

• O atom

• O2H molecule

• solid water

In relation to the box for molecule 1, where do intramolecular forces exist?

• inside the box

• outside the box

Based on the intramolecular forces for molecule 1, draw similar asterisks (*) for the intramolecular forces on the diagram for molecules 2 and 3.

In relation to the molecule, where do intramolecular forces tend to occur?

• Within the molecule

• Between molecules

Two intermolecular forces exist in this image. Where are they positioned relative to the molecules?

• Between the molecules

• Within the molecules

State, in everyday language, the difference between intermolecular and intramolecular forces in terms of where they occur on the molecular level.

• Intermolecular forces occur between molecules, while intramolecular forces occur within a molecule.

• Intermolecular forces occur within a molecule, while intramolecular forces occur between molecules.

• Both intermolecular and intramolecular forces occur within a molecule.

• Both intermolecular and intramolecular forces occur between molecules.

The diagram here represents an arrangement of five molecules. What is the difference between the two ends of each molecule?

• One side is positively charged, the other side is negatively charged

• Both sides are positively charged

• Both sides are negatively charged

Molecules with the property you identified in the last question are known as dipoles: One side is positive, the other is negative.

Consult with your group and reach a consensus on what you think a dipole is. Write down this definition.

• A dipole is a species/molecule that has one positive end and one negative end

• A dipole is a species/molecule that has two positive ends

• A dipole is a species/molecule that has two negative ends

• A dipole has two ends that are identical (either positive or negative)

Consider the attractive forces shown in this image. In terms of the positive and negative ends of the dipoles, where do attractive forces occur?

• Attractive forces occur between the positive end of one molecule and the negative end of another molecule.

• Attractive forces occur between the positive ends of two molecules.

• Attractive forces occur between the negative ends of two molecules.

• Attractive forces occur between the positive end of a molecule and the negative of the same molecule