1. Unit 2: Matter and Energy
Sections 1.1, 1.2, and 16.1

2. Matter’s Properties and Changes
Section 1.2

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

4. Physical Properties
Intensive physical properties don’t depend on how much 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 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 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
Section 1.2

10. Classification of Matter
Two major categories:
Pure substances
Mixtures

11. Pure substances Cannot be separated by physical means Filtration
Evaporation
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

18. Energy Potential – energy w/ respect to position/particle arrangement
Kinetic – energy w/ respect to motion
Radiant – energy in form of EM waves (A.K.A. light)

19. 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 universe is constant

20. Open vs. Closed Systems Open: Interacts w/surroundings
Mass/energy can pass in and out
Ex: uncovered pot boiling on stove
Closed:
Opposite of open!
Ex: thermos (sort of…)

21. 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 universe is constant

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

23. 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 (E = mc2)
Applies to nuclear reactions

24. Heat and Temperature
Section 16.1

25. 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”

26. 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

27. Energy conversion factors
1 calorie = joules  SI unit for energy
1 Calorie = 1000 calories = 1 kcal
Beware of upper- and lowercase c’s!!

28. Activation energy
Energy needed to start a reaction

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 87 0 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?