1. Unit 2: Matter and Energy
Sections 1.2, 1.4, Chapter 3, and Sections

2. Matter’s Properties and Changes
Sections 3.1 and 3.2

3. Physical Properties Describe the look/feel/smell/taste of a substance
Extensive physical properties depend on how much matter is present
Mass
Length
Volume
Width
Shape

4. Physical Properties
Intensive physical properties don’t depend on how much matter is present
Density
Malleability
Boiling point
Melting point
Color
Conductivity
Luster
Odor

5. Chemical Properties
Describe how a substance reacts with another substance
Example
Paper is flammable
Lab bench is not

6. Physical Change No new substance is formed
The change can be easily reversed
Ex:
Ice melts (change of state)
Spoon is bent (change of shape)
CO2 gas is dissolved in H2O

7. Chemical Change A new substance is formed
The change cannot be easily reversed – if at all
Ex:
Paper burns
O2 reacts with Fe to create rust (Fe2O3)
Rule of Thumb – a chemical change has occurred if a…
new solid or gas forms
permanent color/energy change occurs

8. How can a chemical change result in a change in a physical property?
When something new is formed its physical properties are likely different than those of the original substance

9. Classification of Matter
Sections 3.3 and 3.4

10. Classification of Matter
Two major categories:
Pure substances – including elements and compounds
Mixtures – including homogeneous and heterogeneous mixtures

11. Cannot be separated by physical means
Pure substances
Cannot be separated by physical means
Filtration
Evaporation
Chromatography
Elements in a compound could be separated, but only w/a chemical reaction

12. Elements
One kind of atom
Ex:
C (carbon)
O2 (oxygen)

13. Compounds More than one kind of atom
Atoms chemically combined (bonded)
Ex:
CO2 (carbon dioxide)

14. Homogeneous mixtures You cannot see the different parts Ex:
Air
Alcohol mixed w/ water
NaCl dissolved in water
A.K.A. solutions

15. Heterogeneous mixtures
Includes suspensions and colloids
You can see the different parts
Ex:
Italian salad dressing
Granite
Milk

16. Summarizer: Matter

17. Energy and Conservation Laws
Section 15.1

18. Types of Energy
Potential – energy due to particle arrangement (or position)
Kinetic – energy due to motion
Radiant – energy in the form of electromagnetic waves (A.K.A. light)

19. Energy Units Joule – SI unit for energy
calorie – Imperial unit for energy
1 calorie = joules
1 kilocalorie (kcal) = 1000 calories (cal)

20. Law of Conservation of Mass
Matter is never created or destroyed in the universe
It may change state or leave a system, but the total mass of the universe is constant

21. Open vs. Closed Systems Open: Interacts w/surroundings
Matter and energy can pass in and out
Ex: uncovered pot boiling on the stove
Closed:
Opposite of open!
Ex: thermos

22. Law of Conservation of Energy
Energy is never created or destroyed in the universe
It may convert into another type of energy or leave a system, but the total energy in the universe is constant

23. Endothermic vs. Exothermic Processes
Requires energy absorption as heat
Ex: ice melting
Exothermic
Releases energy as heat
Ex: gasoline combustion

24. Activation energy Energy needed to start a reaction
Exothermic – products have a lower potential energy

25. Law of Conservation of Mass-energy
Sum total amount of mass and energy in the universe is constant
Mass may change into energy and vice-versa
Applies to nuclear reactions

26. Heat and Temperature
Sections 15.1 and 15.2

27. Thermal energy vs. Heat
Thermal energy: kinetic energy of the particles in a substance
Heat: thermal energy moving from a hot substance to a cold one
Could also use the phrase “heat transfer”

28. Heat vs. temperature
Temp: measure of average kinetic energy of the particles in a substance
A.K.A average thermal energy
Changes during heat transfer

29. Specific Heat Amount of heat needed to raise the temp of an object
Heat = thermal energy transferred into the object

30. It is May 1 and we are experiencing an extremely hot spring day
It is May 1 and we are experiencing an extremely hot spring day. The air is about F. You decide to go swimming in Lake Pearl. How will the water temperature feel? How does the specific heat of water compare to the specific heat of air?
Water temp will feel cold because water has a higher specific heat than air  takes more energy to increase temp