Mid-Summer Exam Review Of Chemistry

Mid-YEAR EXAMINATION REVIEW PACKAGE

* Everything around us is considered matter. Everything with a mass and a volume is considered matter. * All matter is made of small invisible particles called atoms. * There are 92 different types of atoms in the universe. * Substances that are made up of one type of atom are called pure elements; therefore there are 92 pure elements in the universe. * Substances made up of more than one type of atom are called mixtures. * Mixtures are made up of groups of atoms called molecules. * Molecules that are made of one type of atom are called simple molecules. Examples: O3 , N2 , S8 * Molecules that are made of more than one type of atom are called compound molecules.
Decomposition
3) Phase changes: 3. Synthesis a) Solidification: From Liquid phase to Solid phase 4. Precipitate b) Fusion: From Solid phase to Liquid phase c) Condensation: From Gas phase to Liquid phase d) Evaporation: From Liquid phase to Gas phase e) Deposition: From Gas phase to Solid phase f) Sublimation: From Solid phase to Gas phase

Example: Freezing water will change its phase from liquid to solid. The particles will slide over each other until the temperature gets cold enough so that they slow down. As ice forms, each particle will keep its spot and strongly bond with neighboring particles as in solids. Ice is considered a solid. Ice and water have different densities; however, the particles in the ice have not changed chemically. Therefore solidification is a physical change.
There are four clues to help us identify whether a change occurred to a substance is chemical. Those are:
a) Release of gas. (Ex: bubbles forming)
b) Release of heat or light (Ex: explosion)
c) Creation of a precipitate (Ex: Residue being formed, digestion, exhaust)
d) A color change (Ex: Rust)

Science Review Notes
September 2012 – January
What is its density?
O= m/v=1kg/1L =1kg/per L =1000g/L

1) M=17g, v=10mL D =? 17kg/10mL =1.7g/mL 2) M=2g, v=12mL D =? 2g/12mL =0.167g/mL 3) M=7g, v=21mL D =? 7g/21Ml =0.3g/mL

Object 1) 2g/mL M=11g V=? 11g/26 per mL=5.5mL
Object 2) 0.8g/mL M=16g V=? 16g/0.8g per mL=20mL
Object 3) 3.5g/mL M=7g V=? 7g/3.5g per mL=2mL

Atoms

Components of atoms:

- Electrons (-)
Nucleus
* Neutrons (neutral) * Protons (+)

H (1): 1 electron, 1 proton, 1 neutron
Ca (20): 20 electrons, 20 protons, 20 neutrons
All atoms are the same size, but have a different amount of electrons, protons ad electrons depending on the rank it has in the Periodic Table of Elements.

Characterization
Non characteristic properties:
-shape
-colour
-mass
-volume
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-size
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-freezing point
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-electric conductivity
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Characteristic properties:
Physical:

- density
- boiling point
- melting point
- solubility
- electric