1. Physical and Chemical properties
Notes # 1

2. Physical properties can be observed and measured without changing the kind of matter being studied.
They can be used to classify materials, such as metals and nonmetals
Metals have the following properties: Luster, good conductors, malleable, ductile and high density
Nonmetals are dull insulators(nonconductors) and brittle

3. Melting point: the temperature at which a solid can change to a liquid.
For pure substances a melting point is constant and can be used to identify an unknown substance.
example: ice melts to liquid water at 00 C and 320 F.

4. Boiling point: the temperature at which a liquid changes to a gas.
In pure substances at sea level, boiling point is a constant temperature.
Example: boiling point of pure water at sea level is C and 2120 F.

5. Conductivity: the ability to act as an electrical conductor or insulator
Conductive material allows an electrical circuit to be completed
High conductivity easily allows electricity to flow
Poor conductors are called insulators and do not allow electricity to flow
Many metals are conductors and nonmetals are insulators

6. Color
Can be used with other physical properties to help identify a material
By itself, color is not a good way to identify a substance
Absence of color is also a physical property

7. Hardness and Magnetism
Hardness is the relative resistance of a metal or other material to avoid denting, scratching or bending
Magnetism reacts to forces exerted by magnets and are either repelled or attracted

8. Density depends on its state of matter, solid, liquids or gas
Density is the relationship between the mass of a material and its volume.
Density depends on its state of matter, solid, liquids or gas
High density material has more matter in a smaller space
Density is a constant amount, no matter whether you have a large amount or small amount of a material.

9. Density formula: density =mass/volume
Grams are used for mass measurement
Centimeters cubed or cm3 is used for volume of solids
Milliliters or ml is used for volume of liquids
density tells us how much stuff is in a certain space
For example: some of you have lockers with high density and it is time to clean them out. : )

10. Density problem Using the density formula
If the mass of an object is 20 grams and the volume of the object is 10 ml, what is the density of the object?
Formula d=m/v d=20g / 10ml
Density = 2g/ml
We compare density of an object to water’s density:
If density is less than 1g/ml the object will float
If density is greater that 1g/ml than the object will sink
Will the above object sink or float?

11. Chemical Properties: can be recognized only when substances react chemically with one another; they are not usually visible
1. Ability to burn: when a substance reacts with Oxygen quickly to release light and heat energy
2. Ability to rust: when a substance reacts slowly with oxygen over a period of time
3. Chemical reactivity: the tendency of a substance to react with another substance
When a substance reacts with another substance a change occurs.