1. The Final Hodgepodge! Phase Diagrams
There are 3 basic phases of matter
Solid – molecules are bound together and can not move relative to each other. Solids have a definite shape and volume.
Liquid – molecules have an attraction for each other, but can slide over each other. Liquids have indefinite shape, but a definite volume. .

2. The Final Hodgepodge! Phase Diagrams
There are 3 basic phases of matter
Gas – molecules have no attraction for each other, free to move. Gases have no definite shape or volume.
In order for a solid to become a liquid, enough energy must be added to overcome the intermolecular forces binding the molecules together. .

3. The Final Hodgepodge! Phase Diagrams
A liquid can become a gas when enough energy is added to overcome the attraction of the molecules for each other.
In talking about gases, we learned that pressure, temperature and volume had to be considered. .

4. The Final Hodgepodge! Phase Diagrams
For a substance to undergo a phase change, we need to be concerned with pressure, temperature and energy.
We know that water will freeze at 0°C. Now we need to include that this happens at 101.3kPa or 1atm.
Likewise, water turns to a gas at .

5. The Final Hodgepodge! Phase Diagrams
If you vary the pressure, then the temperature at which a phase change will occur will also change.
This is best shown on a Phase Diagram. .

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8. The Final Hodgepodge! Phase Changes
If you put ice into a glass of water and continually stir it while measuring the temperature, you would find it at 0°C until all the ice melted.
So how can water exist as ice and water at 0°C?
It takes energy to change ice to water. .

9. The Final Hodgepodge! Phase Changes
Until all the ice has changed to water, then all the heat goes to phase change, and none to raising the temperature.
The same holds true for changing water into steam – all the energy added to water at 100 0°C is used for phase change – not temperature change. .

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12. The Final Hodgepodge! Reaction Rates How fast does a reaction occur?
Average reaction rate = Δquantity/ Δt
Since chemist are usually concerned with concentration (molarity).
Reaction rate = mol/L∙s
In a reaction rate formula [ ] are used to indicate molarity.
[NO3] means the molarity of NO3. .

13. The Final Hodgepodge! Reaction Rates How fast does a reaction occur?
It takes energy for a reaction to take place.
The energy needed to sustain a reaction is called the activation energy.
Some reactions can occur without the need for outside energy (molecules colliding provide the energy). .

14. The Final Hodgepodge! Reaction Rates How fast does a reaction occur?
Exothermic reactions typically have a low activation energy and release more energy than needed to sustain the reaction.
Endothermic reactions typically have a high activation energy and tend to absorb energy. .

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17. The Final Hodgepodge! Reaction Rates Factors affecting reaction rates.
Nature of the reactants – we know that Na and Cl are very reactive elements, whereas Ne and Ar hardly will react at all.
Concentration – The more particles colliding, the faster the reaction. The higher the concentration the more particles there are. .

18. The Final Hodgepodge! Reaction Rates Factors affecting reaction rates.
Surface area – granulize sugar will dissolve quicker than cube sugar because there is more surface area available to collide with the water molecules. This is true for every reaction. .

19. The Final Hodgepodge! Reaction Rates Factors affecting reaction rates.
Catalysts – will increase the rate of reaction by lowering the activation energy. .

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21. The Final Hodgepodge! And the winner is . . . .
Enthalpy is a measure of heat content.
Since heat is energy and we know the desire of the universe is for everything to have no energy, then enthalpy is always decreasing.
Entropy is a measure of the disorder of the universe. With no outside help, everything looses order and thus entropy is always increasing. .

22. The Final Hodgepodge! Heat and Temperature are not the same!
On a hot summer day after a rain storm and the sun has come out, have you ever walked barefoot through a puddle of water and noticed how cool it is?
Yet if you walk over a man hole cover after walking thru the puddle, it will just about blister your feet.
Both have received the same energy from the sun, but one is hotter! .

23. The Final Hodgepodge! Heat and Temperature are not the same!
Heat is the energy that flows from a warmer object to a cooler object.
Heat is measured in calories.
1 calorie is the amount of heat needed to raise 1.00g of H2O by 1°C.
Since heat is energy, it can also be measured in Joules (J).
One Joule is calories. .

24. The Final Hodgepodge! Heat and Temperature are not the same!
We learned when talking about gases that temperature is a measure of the average kinetic energy of particles in a substance. .

25. The Final Hodgepodge! While on the topic of energy . . .
We know that kinetic energy is energy due to motion.
How about potential energy?
Potential energy is stored energy.
If you lift a rock from the ground, it has potential energy (it can do work as it falls).
All substances have chemical potential energy. .

26. The Final Hodgepodge! While on the topic of energy . . .
Chemical Potential Energy.
This is the energy stored in a substance and can do work when released.
Gasoline has a lot of chemical potential energy – 1gal = 14 sticks of TNT! .

27. The Final Hodgepodge! Redox Returns! Change in Oxidation Numbers
2K(s) + Br2(g)  2KBr(s)
Changing this to the net ionic equation we get:
2K(s) + Br2(g)  2K+(s) + 2Br-(s)
Notice that potassium went from a neutral charge to a +1 charge (or oxidation number). .

28. The Final Hodgepodge! Redox Returns! 2K(s) + Br2(g)  2K+(s) + 2Br-(s)
Also that Br2 went from being neutral to a -1 oxidation number.
When a substance looses electron(s) then it is said to be oxidized.
When a substance gains electrons then it is said to be reduced. .

29. The Final Hodgepodge! Redox Returns! LEO the lion says GER or LEO GER
Loss of Electrons is Oxidation
Gain of Electrons is Reduction
There is a convention that tells if the number is an oxidation number or an ionic charge:
Ionic charges are written 3+ or 2-.
Oxidation numbers are written +3 or -2. .

30. The Final Hodgepodge! Redox Returns!
Identifying who is oxidize and who is reduced.
2K(s) + Br2(g)  2K+(s) + 2Br-(s)
In this reaction we see the potassium lost an electron so it was reduced.
In the same reaction, bromine gained an electron so it was oxidized. .

31. The Final Hodgepodge! Redox Returns!
Identifying who is oxidize and who is reduced.
2Al + 2Fe3+ + 3O2-  2Fe + 2Al3+ + 3O2-
In this reaction we see the aluminum lost 3 electrons so it was reduced.
Iron gained 3 electrons so it was oxidized.
Oxygen neither gained or loss electrons. .

32. The Final Hodgepodge! Redox Returns!
Another way to look at a redox reaction is in two half reactions:
Fe + O2  Fe2O3
In this reaction the iron went from neutral to
+3. ?
Fe  Fe+3 + 3e-
The oxygen went from neutral to
-2. ?
Fe  Fe+3 + 3e- .

33. The Final Hodgepodge! Redox Returns!
So what happens to just the potassium in the reaction?
K(s) + Br2(g)  KBr(s)
The bromine went from being neutral to gaining an electron.
Br +  K+ + 1e- .