Vapor Pressure and Boiling Point

Liquids with weak intermolecular forces

• contain a lot of kinetic energy
• easily evaporate
• cannot diffuse
• freeze easily

When the atmospheric pressure equals the equilibrium vapor pressure ___ occurs.

• freezing
• melting
• boiling
• sublimation

Why does a gas with a lower vapor pressure have a higher boiling point?

• the molecules need more energy to break free of their attractions to other molecules and change phase from liquid to gas

• the forces of attraction between the molecules are strong

• the substance has low volatility

• all of the answers are correct

Tags

NGSS.HS-PS3-4

When you increase your altitude, the air pressure 

• increases
• decreases
• stays the same

Which model represents a LOWER Vapor Pressure?

• A

• B

Which model represents STRONGER Intermolecular Forces?

• A

• B

water have a low vapor pressure because

• it has strong london dispersion forces acting between its molecules
• it has strong hydrogen bonds acting between its molecules
• it has a weaker force of attraction between its molecules
• it is very volatile

Which substance has the weakest intermolecular forces?

• Substance A, boiling point of 75 °C

• Substance B, boiling point of 105 °C

• Substance C, boiling point of 25 °C

• Substance d, boiling point of 45 °C

The weaker the intermolecular forces of a substance the _____________ the boiling point

• higher

• lower

As pressure decreases, boiling point___

• decreases
• increases
• decreases then increases
• increases then decreases