Evaporation, Boiling Point, and IMFs
Explain how evaporation is a cooling process?
When a liquid evaporates, only the molecules with the highest kinetic energy (temperature) are able to escape the IMFs between all the liquid molecules to turn into a gas. This process causes the cooling of the remaining liquid because molecules with the highest Kinetic Energy have escaped leaving he average Kinetic Energy lower (temperature).
What affects the evaporation rate of a substance?
temperature, humidity, surface area, wind, strength of IMFs
What is atmospheric pressure?
the pressure exerted by the weight of the atmosphere
How is evaporation different than boiling?
EVAPORATION: can happen at any temperature, only surface molecules can vaporize, overall temperature of liquid gets COLDER as evaporation occurs. BOILING: Liquid is being heated, happens at a specific temperature - the point it boils, molecules throughout liquid can vaporize, overall temperature of liquid is maintained as boiling occurs.
Does evaporation heat or cool a liquid?
Evaporation COOLS a liquid!
Define evaporation.
Evaporation is a liquid changing into a gas.
How do molecules evaporate?
Molecules on the surface of a liquid can escape the IMFs pulling them toward the other molecules IF they have enough Kinetic Energy.
How do IMFs affect boiling point?
Substances with stronger IMFs will have a higher boiling point. The molecules need more energy/speed to escape the IMFs and become a gas.
How does atmospheric pressure affect boiling point?
The more molecules "pushing down" on the liquid, the harder it will be for the liquid's molecules to break free.
Define boiling point.
The temperature at which all the molecules of a substance can escape the IMFs of the liquid to become a gas.
What affects boiling point?
IMFs and atmospheric pressure
Temperature can be defined as
The average kinetic energy of a substance
