1. Chemeketa Community College
Properties of Matter
Chapter 4
Larry Emme
Chemeketa Community College

2. Properties of Substances

3. Properties of a Substance
A property is a characteristic of a substance.
Each substance has a set of properties that are characteristic of that substance and give it a unique identity.

4. Physical Properties

5. The inherent characteristics of a substance that are determined without changing its composition.
Examples:
taste
color
physical state
melting point
boiling point
density

6. Physical Properties of Chlorine
2.4 times heavier than air
color is yellowish-green
odor is suffocating or sharp
melting point –101oC
boiling point –34.6oC

8. Chemical Properties

9. Describe the ability of a substance to form new substances, either by reaction with other substances or by decomposition.

10. Chemical Properties of Chlorine
It will not burn in oxygen.
It will support the combustion of certain other substances.
It can be used as a bleaching agent.
It can be used as a water disinfectant.
It can combine with sodium to form sodium chloride.

12. Physical Changes

13. Physical Changes
Changes in physical properties (such as size shape and density) or changes in the state of matter without an accompanying change in composition.
Examples:
tearing of paper
change of ice into water
change of water into steam
heating platinum wire

14. Chemical Changes

15. In a chemical change new substances are formed that have different properties and composition from the original material.
yields + Na
Cl2
NaCl

18. Formation of Copper(II) Oxide
The formation of copper(II) oxide from copper and oxygen is a chemical change.
The copper (II) oxide is a new substance with properties that are different from copper.
Heating a copper wire in a Bunsen burner causes the copper to lose its original appearance and become a black material.
The black material is a new substance called copper(II) oxide.
Copper is 100% copper by mass.
Copper (II) oxide is: 79.94% copper by mass 20.1% oxygen by mass.

19. Formation of Copper(II) Oxide
Neither Cu nor O2 contains Cu2+ or O2-
Copper(II) oxide is made up of Cu2+ and O2-
A chemical change has occurred.

20. Chemical Equations

21. Chemical symbols can be used to express chemical reactions

22. Copper plus oxygen yields copper(II) oxide.
heat
reactants
product
yield

24. Conservation of Mass

25. No change is observed in the total mass of the substances involved in a chemical change.

26. sodium + sulfur  sodium sulfide → 46.0 g 32.1 g 78.1 g
78.1 g reactant
78.1 g product
mass reactants =
mass products

27. Heat: Quantitative Measurement

28. A form of energy associated with small particles of matter.
Heat
A measure of the intensity of heat, or of how hot or cold a system is.
Temperature

29. Units of Heat Energy

30. (exactly) 4.184 Joules = 1 calorie
The SI unit for heat energy is the joule (pronounced “jool” rhymes with fool).
Another unit is the calorie.
4.184 J = 1 cal
(exactly) Joules = 1 calorie
This amount of heat energy will raise the temperature of 1 gram of water 1oC.

31. Specific Heat

32. The specific heat of a substance is the quantity of heat required to change the temperature of 1 g of that substance by 1oC.

33. Specific Heat of Substances
Specific heat (cal/gC)
Water
1.00
Ethyl alcohol
0.511
Ice
0.492
Steam
0.481
Iron
0.113
Copper
0.0921
Gold
0.0312
Lead
0.0305

34. The units of specific heat in calories are:

35. The relation of mass, specific heat, temperature change (ΔT), and quantity of heat lost or gained is expressed by the general equation:
Heat (cal) = mass (g)  specific heat (cal/g C)  ΔT (C)

36. Example

37. Calculate the specific heat of a solid in cal/goC if 391
Calculate the specific heat of a solid in cal/goC if cal raise the temperature of 125 g of the solid from 25.0oC to 52.6oC.
heat = (mass)(specific heat)Δt
heat = (g)(specific heat)Δt
heat = cal
mass = 125 g
Δt = 52.6oC – 25.0oC = 27.6oC
391.5 cal
0.113 cal
g C =

38. Energy in Chemical Changes

39. In all chemical changes, matter either absorbs or releases energy.

40. Energy Release From Chemical Sources Type of Energy Energy Source
Electrical
Storage batteries
Light
A lightstick. Fuel combustion.
Heat and Light
Combustion of fuels.
Body
Chemical changes occurring within body cells.

41. Chemical Changes Caused by
Absorption of Energy
Type of Energy
Chemical Change
Electrical
Electroplating of metals. Decomposition of water into hydrogen and oxygen
Light
Photosynthesis in green plants.

42. The End