1. Physical & Chemical Properties of Matter

2. Matter Matter: anything that has mass and takes up space
Chemistry: the study of matter
Property: attribute, quality, or characteristic of something
Matter has both physical and chemical properties

3. Properties of Matter
Physical Properties: describe the look or feel of a substance, such as color, hardness, density, texture, and phase
Can change when conditions change, but the substance remains the same
Chemical Properties: characterize ability of a substance to react with other substances or transform from one substance to another – flammability, reactivity, heat of combustion, and toxicity
Chemical Bonds: the attractions between atoms that hold them together in a molecule

4. Density Density: ratio of mass to volume for an object
D=m/v (density = mass/volume)
Density of a pure compound or element is a constant
Gold is always g/mL; water is always g/mL
Less dense objects float in more dense objects

5. Viscosity Viscosity: A material’s resistance to flow Physical property
A liquid with high viscosity would be honey, one with low viscosity would be water
Newton stated the only way to change a fluid’s viscosity is to alter its temperature—honey flows more easily when you add heat to it.

6. Changes in Matter
Physical Change: a substance changes its phase or some other physical property but NOT its chemical composition
a piece of paper being cut in half
If it is a physical change, restoring the original conditions will restore the original substance
If you freeze liquid water and then allow the ice to melt, you will again have liquid water

7. Changes in Matter Common signs of a physical change
Texture—rough wood vs. finished wood
Color—painting a car
Shape—folding a piece of paper
Change of state—boiling water

8. Changes in Matter
Chemical Change: any change in a substance that involves a rearrangement of the way atoms are bonded
baking soda reacts with vinegar to form carbon dioxide and water
If it is a chemical change, restoring the original conditions will NOT restore the original substance
If I make cookies from sugar, eggs, and flour, there is nothing I can do to the cookies to get back my original ingredients

9. Changes in Matter Common signs of a chemical change
Color—metal rusting
Noticeable odor—rotten egg; spoiled milk
Formation of precipitate—a solid that forms inside of a solution or another solid
Formation of bubbles— indicates a formation of a gas

10. Matter Matter is either pure or impure
Pure Substance: matter that has a fixed composition (make-up) and definite (unchanging) properties

11. Atoms & Elements
Atom: smallest unit of matter, make up everything around you!
Element: material made up of one type of atom, cannot be broken down by any means, organized in the periodic table
All elements are listed in the periodic table and given an atomic symbol (1-2 letters)
Both are pure substances

12. Compounds
Elements can combine to form compounds, another example of a pure substance
Compounds: form when atoms of two or more different elements bond together
Properties of compounds are different than their elemental components
Compounds are represented with chemical formulas which indicate the atoms present and their proportions

13. Compounds
In a chemical formula, subscripts tell us the ratio in which the atoms combine
NaCl = 1 sodium atom for every chlorine atom
NH3 = 3 hydrogen atoms for every 1 nitrogen atom
Compounds are named according to which elements they contain

14. Compounds 1. metal + nonmetal
Element farther to the left is first, followed by element farther to the right, with the suffix –ide added to its name
NaCl = sodium chloride
2. nonmetal + nonmetal
Add prefixes based on the number of atoms in the element 1 (mono-), 2 (di-), 3 (tri-), 4 (tetra-)
CO2 = carbon dioxide
3. systematic names
Many compounds are assigned common names
NH3 = ammonia

15. Mixtures
Mixture: a combination of two or more substances in which each retains its own properties.
THEY ARE NOT CHEMICALLY BONDED
Mixtures are not pure substances
Most materials are mixtures

16. Mixtures
Heterogeneous: a mixture in which you can see the different components as individual substances
Sand in water; oil and water; pulp in orange juice
Homogeneous: a mixture in which the composition is the same throughout
Air, salt water
Are either solutions or suspensions

17. Mixtures
Solution: all of the components in the mixture are in the same phase
Air is made of gaseous N2 and O2
Saltwater is a liquid solution – water and dissolved sodium chloride are found in a single liquid phase
Suspension: the particles of a substance are finely mixed but not dissolved
Milk is a mixture of proteins and fats in water
Blood is a mixture of blood cells in water

18. Periodic Table
Elements are organized in the periodic table by their properties
Metals are shiny, opaque, good conductors of electricity and heat, and mostly solid at room temperature
Nonmetals are nonmetallic, poor conductors of electricity and heat, may be transparent, and can be either solid, liquid, or gas at room temperature
Metalloids have both metallic and nonmetallic properties—include 6 elements: boron, silicon, germanium, arsenic, antimony, and tellurium

20. Periodic Table
The three main groups of the periodic table are further divided into families
Period: horizontal row
Periodic Trend: gradual change in elemental properties across a period
Group (family): vertical column
Down any group, the properties are very similar