Vapor Pressure and Boiling

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

Liquids with weak intermolecular forces

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

Tags

NGSS.HS-PS1-3

According to the reference table, what is the boiling point of ethanoic acid at 80 kPa?

• 28 ^oC

• 100^oC

• 111^oC

• 125^oC

Which liquid has the highest vapor pressure at 75^oC?

• ethanoic acid

• ethanol

• propanone

• water

Tags

NGSS.HS-PS3-2

At which temperature is the vapor pressure of ethanol equal to the vapor pressure of propanone at 35^oC?

• 35^oC

• 60^oC

• 82^oC

• 95^oC

Tags

NGSS.HS-PS3-4

What is the normal boiling point of water

• 0^oC

• 100^oF

• 50^oC

• 100^oC

Which compound has the lowest vapor pressure at 50°C? Use Table H.

• ethanoic acid

• ethanol

• propanone

• water

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