PhasesEnergyTemp.ppt

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Phases of Matter, Energy

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Phase of Matter



Depends on

strength of forces

of attraction

between particles.

.

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Solids

 Definite shape and volume. _{Definite shape and volume.}

 Most dense phase (_{Most dense phase (}_{Exception is water!)}_{Exception is water!)}  Difficult to compress._{Difficult to compress.}

 Particles vibrate in fixed positions_{Particles vibrate in fixed positions}

 Crystalline lattice structure. _{Crystalline lattice structure.}

 Most attraction between particles._{Most attraction between particles.}

 Note: _Note:

 Amorphous_Amorphous solids include glass,_{solids include glass,}

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Liquids



Definite volume



No definite shape



Hard to compress



Particles slide past each

other



Forces of attraction

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Gases

 No definite shape or volume_{No definite shape or volume}

 Expands to fill container_{Expands to fill container}

 Lowest density_{Lowest density}

 Little attraction between _{Little attraction between}

particles

 “_“Vapor” = a gaseous state of _{Vapor” = a gaseous state of}

something that is normally liquid

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Changes in Phase

Gas

Condensation

Condensation Vaporization Vaporization (Boiling or Evaporating)(Boiling or Evaporating)

Liquid

Solidification

Solidification Melting (fusion)Melting (fusion)

Solid

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Phase Changes

Short Summary video on phases: (1 min)

http://www.youtube.com/watch?v=s-KvoVzukHo&safe=active

Applet: (Excellent)

https://phet.colorado.edu/en/simulation/states-of-matter

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Let’s Skip a Phase

 Sublimation_Sublimation

 Directly from the solid _{Directly from the solid}

phase to the gas phase. phase to the gas phase.

 Happens with substances _{Happens with substances}

with weak intermolecular with weak intermolecular forces of attraction

forces of attraction

 They separate easily!_{They separate easily!}

 Ex: COEx: CO₂₂(s) dry ice, Iodine(s) dry ice, Iodine

CO

CO₂₂(s) → CO(s) → CO₂₂ (g) (g)

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Energy

 Energy_Energy = capacity to do work or produce heat. _{= capacity to do work or produce heat.}

It can be anything that causes matter to move or

change direction.

 Many different types of energy_{Many different types of energy}

 Ex: electrical, thermal, atomic, mechanical _{Ex: electrical, thermal, atomic, mechanical}

 “_“Chemical” energy is the _{Chemical” energy is the}potential energy _{potential energy}stored in _{stored in}

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Law of Conservation of Energy

 Energy can’t be _{Energy can’t be}

created or

destroyed, just

transferred from

one form to another

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PE vs. KE

 Potential Energy_{Potential Energy}

stored energy

 Energy can be stored in _{Energy can be stored in} bonds between atoms bonds between atoms

 Kinetic Energy_{Kinetic Energy}

energy of motion

 All atoms are moving _{All atoms are moving} and vibrating unless at and vibrating unless at absolute zero

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Energy and Changes to Matter

 Exothermic Change:_{Exothermic Change:} A + B → C + D + energy_{A + B → C + D + energy}

 Energy is released or “ex”its_{Energy is released or “ex”its}

 Endothermic Change:_{Endothermic Change:} A + B + energy → C + D_{A + B + energy → C + D}

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Energy During Phase Changes



Solid Liquid or Liquid Gas

 Endothermic _Endothermic

 Energy is absorbed and overcomes attractive _{Energy is absorbed and overcomes attractive}

forces between particles

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

Gas

Liquid, Liquid

Solid

 Exothermic _Exothermic

 As particles come closer together energy is _{As particles come closer together energy is}

released

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Heat Energy

 Also called Thermal energy, it makes particles _{Also called Thermal energy, it makes particles}

move more as it is added

 Measured in Joules or calories._{Measured in Joules or calories.}

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Heat Flow or Transfer

 Heat energy travels _{Heat energy travels} from an object of

from an object of

higher temp. to

one of lower temp.

until both reach

the same temp.

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Temperature



Measure of the

average kinetic energy

(motion) of all the particles in a sample.



Not a form of energy!!!

 But if you add heat energy or take it away, it _{But if you add heat energy or take it away, it}

causes particles to move faster or slower and causes particles to move faster or slower and

thus changes the temp. thus changes the temp.

Heat vs Temp.

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Heat vs. Temperature

 Teacup vs. Bathtub_{Teacup vs. Bathtub}

 Both at 25˚C_{Both at 25˚C}

 Which one contains _{Which one contains}

more heat energy?

 Which one has the _{Which one has the}

greater average KE?

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Temperature Scales Used in

Chemistry

Celsius



Fixed points of scale based on the freezing

point and boiling point of water

 0 °C = water freezes, 100 °C = water boils_{0 °C = water freezes, 100 °C = water boils}

Kelvin



Scale based on lowest temperature possible

 0 K = absolute zero_{0 K = absolute zero}

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Temperature

Scales and

Conversions

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Absolute Zero



Temperature at which particles have

slowed down so much they no longer

possess any kinetic energy.

0 Kelvin

-273° Celsius

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Heating & Cooling Curves

 Graphically represents temp. changes as heat _{Graphically represents temp. changes as heat}

energy is added or taken away.

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Interpreting the Graph

 The slanted portions = _{The slanted portions =}

temp is changing

 Single phase is heating _{Single phase is heating}

up or cooling down up or cooling down

 KE is changing_{KE is changing}

 The flat portions = _{The flat portions =}

temp not changing

 Substance undergoing _{Substance undergoing}

a phase change a phase change

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Heat Equations



Calculates the energy involved when a

substance changes in temperature or

undergoes a phase change.



Use this when temperature of substance

changes use this formula:

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 When Undergoing Phase Change use one of _{When Undergoing Phase Change use one of}

these formulas:

these formulas: TEMPERATURE CONSTANTTEMPERATURE CONSTANT



Q = mHf

_{Use when changing from}_{Use when changing from}

solid to liquid (melting) or solid to liquid (melting) or

liquid to solid (freezing) liquid to solid (freezing)



Q = mHv

_{Use when changing from}_{Use when changing from}

liquid to gas (vaporization) liquid to gas (vaporization) or

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Physical Constants for Water

Table B

Use these constants in Heat Equations

H

_f_f

= heat of fusion = 334J/g

H

_v_v

= heat of vaporization = 2260J/g

Specific Heat Capacity (“c”) = 4.18 J/g x K

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What is Specific Heat Capacity?

Specific Heat

: “c”

Joules of heat needed to raise 1 gram of a

substance 1°C.



Substances have different abilities to absorb

heat when energy is applied depending on

their composition.

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Calorimeter

 Instrument to determine amount of heat lost or _{Instrument to determine amount of heat lost or}

gained in a reaction by measuring changes in the

temp. of water surrounding the system.

Q = mcΔT

Virtual Calorimetry

http://group.chem.iastate.edu/ Greenbowe/sections/

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Multi-step Heat Problems (Honors)

 Need to use more than one of the heat equations and add Need to use more than one of the heat equations and add

up the total heat. up the total heat.

 Note: Specific Heat of different phases of water!_{Note: Specific Heat of different phases of water!}

_H_H

2

2O(s) = 2.10 J/gO(s) = 2.10 J/gxx°C°C

_H_H

2

2O (l) = 4.18 J/gO (l) = 4.18 J/gxx°C°C

_H_H

2

2O(g) = 1.84 J/gO(g) = 1.84 J/gxx°C°C

 Ex: Calculate the heat energy to raise 10 grams of _{Ex: Calculate the heat energy to raise 10 grams of}

water at -25°C to 80°C.

water at -25°C to 80°C.

 Draw a heating curve. Figure out # of steps._{Draw a heating curve. Figure out # of steps.}  1.) Heat ice from -25° to 0°1.) Heat ice from -25° to 0° q = mcq = mcΔΔTT

 2.) Melt ice to liquid at 0°_{2.) Melt ice to liquid at 0°} q = mHf_{q = mHf}

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Heat Lost = Heat Gained (Honors)



When two objects of different temperatures

are placed together in a closed system, heat

flows from hotter to colder object until they

reach same temperature.

mc

Δ

T = mc

Δ

T

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Try This!!



Online App Demonstrates Specific Heat

and Calorimetry

 http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/_{http://elearning.classof1.com/demo/2D_Lab/Chemistry/specificHeat/}

specificHeat.html

http://www.youtube.com/watch?v=s-KvoVzukHo&safe=active

https://phet.colorado.edu/en/simulation/states-of-matter

http://www.harcourtschool.com/activity/states_of_matter/

http://www.youtube.com/watch?v=8tHOVVgGkpk