1. Physical versus Chemical Properties
Chapter 2 Section 2
Describing matter

2. Reviewing MATTER Matter: anything that has mass and takes up space
Mass – the amount of matter in something
Volume – the amount of space something occupies
Which of the following is matter?
A car?
A box?
You?

3. What is a property?
Property: a characteristic of a substance that can be observed

4. Physical Property
Physical property: a property that can be observed without changing the identity of the substance.
Examples:
luster
malleability: the ability to be hammered into a thin sheet
ductility: the ability to be stretched into a wire
melting point
boiling point
density
solubility
specific heat

5. Physical Properties Color Shape Size Density Melting Point
Boiling Point

6. Example of Physical Property
The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.
Hardness, color, melting point and density are all physical properties.

7. Special Physical Properties
Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure
water = 0oC
Boiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure
water = 100oC

8. Thermal
Density
Solubility
State
Ductility
Malleability

9. Chemical Properties
Chemical property: a property that can only be observed by changing the identity of the substance

10. Chemical Properties Examples of Chemical Properties
Reactivity with oxygen
Nonreactivity with oxygen
Flammability
Nonflammability

11. Chemical Properties

12. Comparison of Physical and Chemical Properties

13. Density Density is the amount of mass per unit of volume.
Density can be used to identify a substance.
The density of water is 1.0g/mL

14. Density Calculations Calculations:
D = m/V
Ex: A cube has a mass of 2.8 g and occupies a volume of 3.67 ml. Would this object float or sink in water?
Mass = 2.8 g Volume = 3.67 mL
D = 2.8g/3.67 mL= 0.76 g/mL
This object would float in water because its density is less than water (1.0 g/mL).

15. More Density Calculations
Ex: A liquid has a mass of 25.6 g and a volume of 31.6 mL. Use the table below to identify the substance.
M=25.6 g V=31.6 mL
D = 25.6 g/31.6 mL
D= 0.81 g/mL
The substance is ethanol.

16. Physical Change
Physical change is the change that affects one or more physical properties of a substance.
Imagine breaking a piece of chalk into two pieces. What are you changing? What is not being changed?
Physical changes do not change the identity of the matter involved

17. Physical Change Freezing water for ice cubes Sanding a piece of wood
Cutting your hair
Crushing an aluminum can
Bending a paper clip
Mixing oil and vinegar

18. Chemical Change
Chemical change happens when two or more substance are changed into one or more new substances with different properties.
Properties of a substance describe which chemical changes will or will not happen
Chemical change and properties are not the same, a change is the process in which it changes

19. Chemical Change Examples of Chemical Changes Soured milk
Effervescent tablets
Statue of Liberty
Baking a cake

20. Chemical Change Clues that chemical change has occurred
Changes in color
Heat
Fizzing and foaming
Production of sound or light