1. Physical & Chemical Properties & Changes

2. Physical Property
Physical property = a characteristic of matter that can be observed or measured without changing the identity of the substance
Ex: mass volume
density hardness
color malleability
ductility luster
solubility viscosity
melting, boiling, freezing points
ability to conduct heat & electricity

3. Malleability
Malleability = capable of being shaped or formed (metals are malleable)

4. Ductility
Ductility = ability to be pulled or stretched into wires

5. Luster
Luster = “shiny” or reflects light

6. Solubility
Solubility = the ability to dissolve

7. Viscosity Viscosity = “liquid thickness”
The thicker the liquid the slower it will pour

8. Density Density = mass/volume D = m/V
Units for density include (but there are more!)
g/mL or g/cm3
kg/L or kg/m3
Density can be used to identify unknown matter because density is a property of matter that doesn’t depend on size!
Ex: Lead has a density of g/mL
Therefore, all pure samples of lead will have a density of g/mL
Ex: Copper has a density of 8.92 g/mL
Therefore, all pure samples of copper will have a density of 8.92 g/mL

9. Which is more dense liquid water or frozen (solid) water????
Density
Density of H2O at 20 °C (68 °F)= g/mL (it’s ok if we round to 1.00 g/mL)
Density of H2O at 0 °C (32 °F) = 0.92 g/mL
Which is more dense liquid water or frozen (solid) water????
Liquid water! This is why ice floats…and fish don’t die in lakes in the winter!

10. Density
If an object is more dense than water it will generally sink in water
If an object is less dense than water it will generally float in water
Ex: If mercury (D = 13.6 g/mL), copper (D = 8.92 g/mL), and water at 20 °C (D = 1.00 g/mL) are combined what will be the order of the layers based on their densities?

11. Density
Water
Copper
Mercury

12. Physical Property
Physical properties can be described further as extensive or intensive.
Extensive Property = property dependent of the amount of substance present or size
SIZE MATTERS!
Ex: mass, volume, length
Intensive Property = property independent of the amount of substance present or size
Ex: density, melting point, boiling point, freezing point, malleability, ductility, viscosity, all chemical properties
SIZE DOESN’T MATTER!

13. Intensive or Extensive?
Mass
Color
Density
Shape
Melting point
Texture

14. Physical Changes
Physical changes = changes that alter matter but don’t change its chemical composition (make-up)
Change appearance but not chemical make-up
Ex: cut carrots shred paper
chop wood grind coffee
break glass melt candle wax
boil water freeze alcohol
dissolve NaCl in water

15. Physical Change Action Words
Cutting Bending Grinding
Crumple Split Crush
Dissolve
Melting
Boiling (Vaporize)
Freezing
Sublime
Condense
Deposition
Phase Changes

16. Chemical Property
Chemical property = the ability or inability of a substance to react

17. Chemical Changes
Chemical change = any change that causes one material to turn into a new material with a different chemical make-up
Ex: Na+ reacting with Cl-
road kill decomposing
bananas rotting
grapes fermenting
iron rusting
copper oxidizing
cooking eggs
grass growing

18. Chemical Changes
Chemical changes can also be called a chemical reactions.
Chemical reactions can be represented by chemical equations.
Reactants = starting substance(s)
Products = new or end substance(s)
Reactants and products separated by an arrow
Reactants → Products

19. Chemical Changes
Law of Conservation of Mass = matter is neither created nor destroyed in ordinary chemical reactions, it’s simply rearranged.
The mass (or amount) of the reactants and the products is equal.
Ex: 2 NaN3  Na N2
150g 50g g
Na2SO ZnBr2  ZnSO NaBr
100g g 130g g

20. Chemical change action words
React Explode
Decompose Rot
Ferment Rust
Oxidize Corrode
Cook (with heat) Grow

21. Chemical Change Signs of a chemical change or reaction
1. Temperature change
Exothermic reaction = a reaction that gives off energy
- warm/hot to touch
Endothermic reaction = a reaction that absorbs energy
- cool/cold to touch
2. Spontaneous change in color
Ex: like when things rust, rot, burn
3. Gas produced
4. Odor given off
5. Formation of precipitate (solid)

22. CHEMICAL OR PHYSICAL CHANGE?
Baking cookies
Boiling water
Dissolving salt
Burning firewood
Milk spoiling
Metal rusting
Tearing paper
Melting ice