5) Vapor Pressure and Boiling Points

What is boiling?

a liquid system absorbs energy and breaks IMFs and changes to the gas state

What is a liquid system that absorbs energy and breaks IMFs and changes to a gas state?

boiling

What is boiling point?

temperature at which a substance undergoes boiling

What is the temperature at which a substance undergoes boiling?

boiling point

What does stronger IMFs mean?

a higher boiling point

What means a higher boiling point?

Stronger IMFs

When do gas particles exert pressure?

when they collide with a surface

What exerts pressure when they collide with a surface

gas particles

More particles =

more pressure

more pressure =

more particles

What is vapor pressure?

as molecules evaporate, the gas particles exert a pressure on the liquid

What is the process when molecules evaporate, gas particles exert a pressure on the liquid?

vapor pressure

When does vapor pressure increase?

As the temperature increases because more molecules can escape

What increases as the temperature increases because more molecules can escape?

vapor pressure

What is the temperature at which its vapor pressure equals atmospheric pressure?

the boiling point

The boiling point is the temperature at which what happens?

its vapor pressure equals atmospheric pressure

When does the normal boiling point occur?

at 760 mm Hg

What occurs at 760 mm Hg?

the normal boiling point

Strong intermolecular forces =

high melting/boiling points and low vapor pressures

High melting/boiling points and low vapor pressures =

strong intermolecular forces

Weak intermolecular forces =

low melting/boiling points and high vapor pressures

Low melting/boiling points and high vapor pressures =

weak intermolecular forces

Larger molecules usually have stronger what?

stronger London dispersion forces because there’s more electrons; more polarizability

What usually has stronger London dispersion forces because thers’s more electrons; more polarizability?

larger molecules

What usually has higher boiling and melting points?

very large molecules because there’s greater surface area that can form more IMF interactions

Because there’s greater surface area that can form more IMF interactions, very large molecules usually have what?

higher melting and boiling points

Why do substances with stronger IMFs have higher boiling points?

because the vapor pressures are lower

What do stronger IMFs have because the vapor pressures are lower?

higher boiling points

What is the order of IMFs weakest to strongest?

London dispersion, dipole dipole, hydrogen bonding, and ion dipole

London dispersion, dipole dipole, hydrogen bonding, and ion dipole is the order of IMFs weakest to strongest or strongest to weakest?

weakest to strongest