2. To compare the various states of matter in terms ofpotential and also kinetic energy
3. Define the significant events that happen along a heatingcurve.
You are watching: Is the evaporation of water endothermic or exothermic
4. Translate a step diagram.
Key Terms:
vaporization condensationevaporation equilibrium vapor pressureboiling allude heat that vaporization freezingpoint heat of fusionsublimation deposition heatingcurve step diagram
Notes: (14-4)
Matter top top Earthexists as either liquid, solid, or gas. Various other than water, most matterexists in a solitary phase (liquid, solid, or gas) but can it is in made to adjust phaseby including or deleting pressure or temperature.
Energy and also PhaseChanges
According to thekinetic-molecular theory, a substances phase is identified by the balance the itskinetic and also intermolecular forces. What this method is that you have the right to convertmatter indigenous one phase to one more by simply including or deleting kinetic energy(heat). When attempting to know the phase changes it is crucial toremember what is occurring in endo and exothermic reactions.
(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 to solid - freezing | |
| gas to liquid - condensation | |
| gas to solid - deposition |
Evaporation
Evaporation is again explained by theKinetic-molecular theory. Once the kinetic energy of the molecule in aliquid come to be greater 보다 the intermolecular attractions between them,evaporation occurs.
| within a liquid, evaporation is constantly occurring come some level at the surface of the liquid | |
| Temperature and evaporation price are straight related | |
| Liquids with high evaporation rates are claimed to be volatile - typically flammable because of the visibility of essential materials and also oxides | |
| Evaporation cools a surface or solution by removing the molecules with the highest possible kinetic energy | |
| Most remedies in a closed container room in liquid-vapor equilibrium | |
| condensation and evaporation rates are equal | |
| price of molecule leaving the solution are equal to the molecule entering the liquid | |
| The solution is at equilibrium vapor pressure |
Boiling Point:
The boiling allude of a fluid is straight relatedto the vapor press of the liquid. Vapor push is a measure of thevapor current in a liquid. As soon as the vapor pressure equals the atmosphericpressure boiling occurs. The is important to remember the vaporization isan endothermic procedure as warm is eliminated from the liquid with boiling.
| vapor press of a fluid is straight related come the temperature applied to the liquid | |
| the boiling suggest is directly related come the atmospheric pressure exerted on the solution | |
| boiling occurs when the vapor push = 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 Melting:
The freezing and melting points of a liquid existat the same temperature and represent an equilibrium in between the fluid andsolid phases.
| melting and freezing points space not greatly impacted by atmospheric pressure | |
| melting relies on the warm of blend which choose the boil is an endothermic process | |
| freezing supplies the very same amount of power as the warmth of fushion bu is an exothermic process |
Heating Curves:
((server.chem.ufl.edu/~itl/2045_s99/ lectures/FG11_024.GIF))
The heater curve is a depiction of thephases of a substance contrasted to the temperature and also internal power of asubstance. The blue lines represent the different phases the a substancewhile the red lines stand for the heats of fusion and vaporization.
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| endothermic reactions move from left to right as the products increase in kinetic energy and also become much less organized |
Phase Diagrams
((server.chem.ufl.edu/~itl/2045_s99/ lectures/FG11_024.GIF))
The phase diagram is another representation ofthe internal energy of a substance compared with the pressure and temperature ofits surroundings.
| temperature and pressure are inversely related to the process of vaporization | |
| pressure has small effect ~ above the melting and freezing the a substance | |
| the triple suggest is a point where all three phases take place in equilibrium |
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