2. To compare the various states of matter in terms ofpotential and kinetic energy

3. Describe the significant events that occur along a heatingcurve.

You are watching: Is water evaporating endothermic or exothermic

4. Interpret a phase diagram.

Key Terms:

vaporization condensationevaporation equilibrium vapor pressureboiling allude heat of vaporization freezingpoint warmth of fusionsublimation deposition heatingcurve phase diagram

Notes: (14-4)

Matter on Earthexists as either liquid, solid, or gas. Other than water, many matterexists in a solitary phase (liquid, solid, or gas) but can be made to change phaseby adding or deleting press or temperature.

Energy and PhaseChanges

According come thekinetic-molecular theory, a substances phase is identified by the balance the itskinetic and intermolecular forces. What this method is the you have the right to convertmatter native one step to one more by simply adding or deleting kinetic energy(heat). When attempting to understand the phase transforms it is crucial toremember what is developing in endo and also exothermic reactions. Endothermic - power is being absorbed - bonds space breaking - assets are less ordered Exothermic - power is gift released - bonds are being developed - commodities are much more ordered


(server.chem.ufl.edu/~itl/2045_s99/ lectures/FG11_024.GIF)

Changesin State:

liquid to gas - vaporization, by process of evaporation
solid come gas - sublimation
liquid come solid - freezing
gas to fluid - condensation
gas come solid - deposition


Evaporation is again described by theKinetic-molecular theory. When the kinetic energy of the molecule in aliquid become greater than the intermolecular attractions between them,evaporation occurs.

within a liquid, evaporation is always occurring come some level at the surface ar of the liquid
Temperature and evaporation rate are directly related
Liquids with high evaporation prices are said to it is in volatile - typically flammable because of the visibility of organic materials and also oxides
Evaporation cools a surface ar or solution by removed the molecules v the highest possible kinetic energy
Most options in a closeup of the door container space in liquid-vapor equilibrium
condensation and evaporation rates are equal
rate of molecule leaving the solution room equal to the molecule entering the liquid
The systems is in ~ equilibrium vapor pressure

Boiling Point:

The boiling suggest of a liquid is directly relatedto the vapor press of the liquid. Vapor push is a measure up of thevapor current in a liquid. As soon as the vapor pressure equals the atmosphericpressure boiling occurs. The is crucial to remember that vaporization isan endothermic process as warmth is removed from the liquid through boiling.

vapor push of a fluid is straight related come the temperature applied to the liquid
the boiling point is straight related come the atmospheric press exerted top top the solution
boiling occurs as soon as the vapor press = atmospheric pressure
the temperature the a liquid will certainly remain consistent at the boiling allude until every one of the fluid is vaporized.

Freezing and also Melting:

The freezing and melting points of a fluid existat the very same temperature and also represent one equilibrium in between the fluid andsolid phases.

melting and freezing points are not greatly impacted by atmospheric pressure
melting relies on the heat of combination which choose the cook is one endothermic process
freezing supplies the exact same amount of energy as the warmth of fushion bu is one exothermic process

Heating Curves:


((server.chem.ufl.edu/~itl/2045_s99/ lectures/FG11_024.GIF))

The heating curve is a representation of thephases the a substance contrasted to the temperature and also internal power of asubstance. The blue lines represent the various phases that a substancewhile the red lines represent the heats of fusion and vaporization.

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endothermic reactions move from left to right as the commodities increase in kinetic energy and become much less organized

Phase Diagrams


((server.chem.ufl.edu/~itl/2045_s99/ lectures/FG11_024.GIF))

The step diagram is another representation ofthe internal energy of a substance contrasted with the pressure and temperature ofits surroundings.

temperature and pressure are inversely regarded the procedure of vaporization
pressure has little effect on the melting and also freezing that a substance
the triple allude is a suggest where all 3 phases take place in equilibrium