Fluid: a substance that can flow and therefore take the shape of its container

Surface tension: a force that tends to pull adjacent parts of a liquid’s surface together, thereby decreasing the surface area

Capillary action: the attraction of the surface of a liquid to the surface of a solid – causes the meniscus when water is in a glass cylinder

Surfactant: (surface active agent) decreases the surface tension of water by interfering with the Hydrogen bonding between water molecules

Soaps and detergents

Allows the water to be attracted to other particles such as dirt, grease, etc.

States of matter – solids and liquidsStates of matter – solids and liquids

Phase changes occur because of changes in

energy!

Vaporization: Change from liquid to gas - there are two methods –both require the addition of energy

evaporation: process by which particles escape from the surface of a nonboiling liquid and enter the gas state

Evaporation is what occurs when you leave a glass of water sitting out

Boiling: rapid conversion of liquid into gas – caused by the vapor pressure inside the liquid being equal to the atmospheric

pressure around the liquid

boiling occurs because of pressure – you can add heat and build pressure inside the liquid or you can lower the external pressure to meet to liquid’s internal pressure – either way boiling will occur

Equilibrium vapor pressure: pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature

Boiling point: Temperature at which equilibrium vapor pressure of the liquid equals the atmospheric pressure

Normal = 1 atmosphere

Normal boiling point: temperature at which a substance will boil at 1 atm1 atm of pressure

For water it is 100OC or 212OF

Volatile liquid: liquid that evaporates readily at room temperature

These substances have low boiling points

NOT the same as explosive – although many volatile substances are also explosive vapors

Molar heat of vaporization: amount of heat energy needed to vaporize one mole of a liquid at its boiling point

NOT the energy to get the liquid to the boiling point – just the energy to change it into a vapor once it has reached its boiling point

q = m Hv formula to calculate the energy for a phase change from liquid to gas

Vaporization is an ENDOTHERMIC process – whether it is evaporation or boiling

Endothermic means you have to add heat – you have to turn on the burner to get a pot of water to boil

To calculate the energy for 200 g of water –

q = (200 g)(2260 J/g)

q = 452000 J = 500000 J (with sig figs)

Freezing: physical change from liquid to solid by the removal of heat

Freezing point: temperature at which the solid and liquid states are in equilibrium

Condensation: gas to liquid – caused by removing heat from the gas or the air no longer being able to hold the gas

You have now looked at converting from liquid to gas and back again – next we will look at liquid to solid and back again.

Normal freezing point: temperature at which a liquid becomes a solid at 1 atm.

Molar heat of fusion: amount of heat energy required to melt one mole of a solid at its melting point

Again the formula for the actual conversion from one state to another is:

q=mHf

Melting: physical change of a solid to a liquid by the addition of heat

Melting point: temperature at which a solid becomes a liquid

Since we have looked at solid to liquid and back again,

we will investigate the solid phase a little more in-depth

Crystalline solid: simply means it contains crystals; consist of crystals

Crystal: a substance in which the particles are arranged in an orderly, geometric, repeating pattern.Examples would be diamond, quartz, table salt, emeralds, etc.

Crystal structure: the total three-dimensional arrangement of particles of a crystal

Amorphous solid: particles are arranged randomly – “without shape” – an example would be soot as seen here – no regular pattern (crystal)

Isomorphous: crystals of different solids with the same crystalline structure – any substances that have the same crystal look – ie. Ruby, emerald, sapphire

Polymorphous- - a single substance having two or more crystalline shapes.

ie: Carbon- graphite, diamond, soot or coal, etc

Unit cell: smallest portion of a crystal lattice that shows the three dimensional pattern of the entire lattice – simplest unit of a crystal

There are 14 known unit cells – the 7 to the left here are just samples

Supercooled liquid: substance that retains

certain liquid properties even at

temperatures at which they appear solid

**HONORS **HONORS Unit cells that you need to know – Unit cells that you need to know – draw these 3 in your notesdraw these 3 in your notes

Simple cubic:Simple cubic:

Body centered Cubic:Body centered Cubic:

Face centered cubic:Face centered cubic:

There are 4 types of crystals:

1) Ionic – these are ionic compounds – (metal/nonmetal usually)

2) Covalent network – these are covalent compounds that are usually solid at room temperature – ie. Quartz, diamond, glass

3) Covalent molecular – these are covalent compounds that are usually gases at room temperature – ie. CO2, Ar, CO, NO2

4) Metallic – can be either pure metals or alloys

Hydrated crystal-Hydrated crystal- crystal which contains hydrated ions (H crystal which contains hydrated ions (H22O molecules bonded O molecules bonded

to ions in the crystals.)to ions in the crystals.)

Written as Written as CuSO CuSO44. . 5H5H22OO

AnhydrousAnhydrous- without water- without water

A hydrated crystal can become an anhydrous crystal by heating to remove the water (drying the crystal)

Also an anhydrous crystal can become hydrated by simply adding water

Hygroscopic: A crystal that starts out as anhydrous and captures water itself to make itself hydrated – it captures the water directly from the air.

An example would be the little white silica packs you find in shoes and electronics – they are suppose to keep the moisture from harming whatever they are packed with

DeliquescentDeliquescent- Substances so hygroscopic that they take up enough water from the - Substances so hygroscopic that they take up enough water from the air to dissolve and form a solutionair to dissolve and form a solution

NaOH is an example of a substance that is deliquescentNaOH is an example of a substance that is deliquescent

**HONORS**HONORS Liquefaction Liquefaction- Condensation of substances that are normally gasses- Condensation of substances that are normally gasses

This is how you get liquid nitrogen This is how you get liquid nitrogen

SublimationSublimation – change from solid directly to a gas – change from solid directly to a gas

ie. – ice in the freezer or snow on a below freezing dayie. – ice in the freezer or snow on a below freezing day

DepositionDeposition: reverse of sublimation the gas is changed directly into a solid : reverse of sublimation the gas is changed directly into a solid

ie. - frost on your car in the morningie. - frost on your car in the morning

EQUILIBRIUMEQUILIBRIUM: dynamic condition in which two opposing processes/changes occur at equal rates in a closed system

Le Chatlier’s principleLe Chatlier’s principle: when a system at equilibrium is disturbed by the application : when a system at equilibrium is disturbed by the application of a stress, it attains a new equilibrium position that minimizes the stressof a stress, it attains a new equilibrium position that minimizes the stress

STRESS = concentration, pressure, or temperature – change any of these 3 and STRESS = concentration, pressure, or temperature – change any of these 3 and you cause the system to “shift”you cause the system to “shift”

Think of Le Chatlier as a see-saw – what happens on one end must be balanced by a move either toward something missing or away toward something missing or away from something addedfrom something added

When extra NH3 is added to the following system at equilibrium:3 H2(g) + N2(g) <--> 2 NH3(g)

The system will “shift” to the left or toward the reactant. (Adding more NH3 increases the concentration of NH3 and that is a stress)

Another generic example:

Solid + heat liquid

Adding heat will cause a shift to the right

Adding liquid will cause a shift to the left

• Adding more reactant will drive the forward reaction.• Adding more product will drive the reverse reaction.• Removal of reactants or products will shift the equilibrium in the directionneeded to produce more of the substance that was removed.

2 NO2 (g) N2O4 (g) + 58.0 kJPredict the effect of each of the following changes on this system at

equilibrium (drive forward reaction, drive reverse reaction, no effect).a) add N2O4 b) remove NO2

c) increase the volume d) decrease the temperaturee) Add N2Answers:

a) Shift left toward reactants or reverse

b) Shift left or reverse

c) Shift left – because increasing the volume decreases the pressure and the side with the most gas is most effected by pressure – so the reactant side has 2 moles of gas and the drop in pressure is similar to removing something from the reactant side

d) Shift right toward the products – because the heat is on the product side – removing heat cause the shift toward the removed piece

e) NO effect – it is not involved in the reaction – only temp., pressure, and concentration of substances involved in the reaction can cause stress

Do NOT copy the next slide – just READ it

Phase diagram-Phase diagram- graph of pressure vs. temp. that shows the conditions under graph of pressure vs. temp. that shows the conditions under which they phases of the substance exists.which they phases of the substance exists.

Triple point-Triple point- indicates the temp. and pressure conditions at which the solid, liquid, indicates the temp. and pressure conditions at which the solid, liquid, and vapor of a substance can coexistand vapor of a substance can coexist

Critical point-Critical point- point where critical temp. and critical pressure cross on the diagram point where critical temp. and critical pressure cross on the diagram

Critical tempCritical temp.- Temperature above which the substance cannot exist in the .- Temperature above which the substance cannot exist in the liquid state. (Tc=373.99liquid state. (Tc=373.99OOC for HC for H22O) O)

Critical pressure- Critical pressure- (Cp) lowest pressure at which the substance can exist as a (Cp) lowest pressure at which the substance can exist as a liquid at the critical temp. Pc(Hliquid at the critical temp. Pc(H22O)= 217.75 ATM.O)= 217.75 ATM.

Copy the graph without the numbers

Freeze drying-Freeze drying- method of preserving food method of preserving foodFreeze the food, allow the water to sublimate and now you have frozen and dry Freeze the food, allow the water to sublimate and now you have frozen and dry food = freeze driedfood = freeze dried Add water and you re-hydrate the foodAdd water and you re-hydrate the food

waterwater•Most important liquid on earth, 75% of the earth. •Many unique properties due to hydrogen bonding

Hydrogen bonding- Attractive force, not as strong as an actual bond, between H+ and an electronegative element in another molecule – must involve F, N, or O to be hydrogen bonding – this is the force that holds DNA together

Water has 4 hydrogen bonds when frozen – may have 12 or more in the liquid phase – this is why water expands when it freezes

Bond angle between H is 105 degrees

Water has a high heat capacity- this means it will hold a lot of heat – that’s why the first few nights in fall when the air temperature is below freezing the ponds don’t freeze

Water has the highest heat vaporization of any room temp. liquid.high heat of vaporization means it takes a lot of energy to get water to vaporize – this allows us to sweat and stay cool – in order for the sweat to leave our skin it has to vaporize – this requires the addition of heat, where does this heat come from? – our bodies – the heat the water takes as it evaporates makes us feel cooler

Water is most dense at 4OC. – allows 4OC water to stay on the bottom of bodies of waterThis fact creates circulation in spring and fall in ponds and lakesAs the water cools it sinks, then when water drops below 4OC it stays on top - top freezes, bottom is still 4OC (you do not have to draw these pictures)

Assignment:Assignment:

Page 403 # 18-22Page 403 # 18-22

Page 409 #24-26Page 409 #24-26

Page 414 #31,35,43,44,49,50,53,54,55,57,58,60Page 414 #31,35,43,44,49,50,53,54,55,57,58,60