Review and Final
Post date: Jan 20, 2009 2:54:20 PM
Final is Tuesday for block 2 and Wednesday for block 3
Review
Chapter 2 - Matter
Classifying Matter
Matter is anything that is made of atoms and takes up space
All matter is either and element, a compound, or a mixture
Element - made of only one kind of atom
Compound - each molecule of a compound contains two or more elements that are chemically bonded
Mixture - Combination of elements and/or compounds that are not chemically bonded
Elements and compounds are pure substances, mixtures are not
Properties of Matter
Physical Properties
Can be observed without changing the identity of the substance
Examples: color, mass, melting point, boling point, density
Density = mass / volume
Chemical Properties
describes how a substance changes into a new substance, either by combining with other elements or by breaking apart into new substances
Examples: flammability and reactivity
Changes of Matter
Physical Changes
Affect one or more of the physical properties of a substance without changing its identity
Examples: melting, freezing, crushing, cutting, bending
Chemical Changes
Substance(s) are changed into new substances with different properties
Examples: burning, alka-seltzer in water, digesting, breathing
Breaking them down
Mixtures can be separated physically
Compounds must be broken down through a chemical change
Chapter 3 - States of Matter
Matter and Energy
Kinetic Theory - All matter is made up of atoms and molecules that are constantly in motion
States of Matter - matter can be classified as solid, liquid, or gas based on whether the shape and volume depend on the container or not
Energy's Role - Because they are in motion, all particle of matter have kinetic energy
Changes of State
The identity of a substance does not change, but the amount of energy it holds does
Mass and energy are both conserved (neither can be created or destroyed)
Fluids
Pressure
Fluids exert pressure equally in all directions
P = F / A
Buoyant Force
Fluids exert an upward buoyant force on matter
Pascal's Principle
If pressure is changed at one point in a fluid, the pressure changes by the same amount at all other points in the fluid
Fluid in motion
Fluids move faster through smaller openings than larger ones
The faster a fluid is moving, the lower the pressure in that fluid
Behavior of Gases
Properties of Gases
Expand to fill their container
Low densities
Compressible
Mostly empty space
Gas Laws
Help predict behavior of gases given certain changes
Chapter 6 - The Structure of Matter
Compounds and Molecules
Chemical Bonds - The forces that hold atoms or ions together
Chemical structure - the shape of compounds, shown with various models
The structure of a compound determines its properties
Ionic and Covalent Bonding
Atoms bond to complete their outer electron level
Ionic - one atom gives electrons to another
Covalent - electrons shared between several atoms
Metallic - electrons shared between all atoms in a substance
Polyatomic ion - group of bonded atoms that act as a single unit
Compound Names and Formulas
Ionic - names of ions, anion ending changed to -ide
Covalent - names of elements, farthes to the right changed to -ide, use prefixes to tell number of each type of atom
Empirical formulas - smallest whole-number ratio of atoms in a compound
Chapter 8 - Solutions
Solutions and other mixtures
Heterogeneous Mixtures
No fixed composition
Amount of each substance varies from sample to sample
"chunky"
Homogeneous Mixtures
Looks uniform, even under a microscope
Individual components are too small to be seen
Mixing at the molecular level
How Substances Dissolve
Water
Universal solvent - dissolves many substances
Polar molecules make it a good solvent
The dissolving process
Molecules at the surface of the solute get hit by molecules of the solvent
Collisions and attractive forces from the solvent knock molecules of the solute off
Rate depens on
Temperature - faster moving particles knock off pieces more easily
Size of solute pieces - more surface area = more of solute exposed
Stirring - moves solvent closer to solute, moves dissolved particles away