Unit 12: Liquids and Changes of State

what is the percent of water that your body is made out of?

70% is water (B)

what is the percent of water the earth surface is made out of?

70%(E)

Evaporation

The process by which liquid water transforms into vapor, typically due to heat.

Boiling point

The conditions at which liquid turns into gas(bubbles) below the surface of the liquid

What type of mechanism is Evaporation?

endothermic; it’s surrounding gets cool

Boiling Point equation

vapor pressure = external pressure

Heat of Vaporization

The amount of heat energy associated with change of state liquid and vapor

Heat of Vaporization equation

Heat → Potential Energy → Kinetic Energy

Condensation

The process by which a gas transforms into a liquid

Condensation equation

gas→ liquid

Condensation mechanism

Fast moving molecules stick together and lose energy, forming a liquid; exothermic, it warms up it’s surrounding

Melting Point = Freezing Point

the temperature at which solid and liquid can both exist

Melting Point = Freezing Point mechanism

change of state liquid to solid and also solid to liquid; endo/ectothermic processes

Heat of Fusion

the amount of energy required to change a substance from solid to liquid at its melting point

Heat of Fusion endothermic

solid to liquid; melting and heating

Heat of Fusion exothermic

liquid to solid; freezing and cooling

Heating of Vaporization Endothermic

liquid to gas; boiling and heat in

Heating of Vaporization Exothermic

gas to liquid; condensation and heat out

Sublimation

solid to gas; heat in; endothermic

Why is water boiling point different?

hydrogen bonding

The hydrogen end has partial

positive charge

The oxygen end has partial

negative charge

Hydrogen bonding

the strongest electrostatic attraction between different molecules that happens when a hydrogen atom is attached to very electronegative atom

Hydrogen bonding is responsible for

high melting point, high boiling point, heat of fusion, and heat of vaporization in water and explains why water dissolves salt but oil

Organic

likes dissolve like
non polar
hydrocarbon
water molecules hydrogen bond with each other