Sunday, July 22, 2012

Chemistry: What is Matter?

My teacher in Chemistry discussed to us about Matter and I have thought an idea that somehow I can share what I have learned based from my Chemistry teacher. Here are the parts of the things I take down notes out from her discussion.

Matter is anything that a:) has mass  b.) takes up space
Mass is a measure of the amount of "stuff" (or material) the object contains (don't confuse this with weight, a measure of gravity)
Volume is a measure of the space occupied by the object.


Describing Matter
Properities used to describe matter can be classified as:
1. Extensive - depends on the amount of matter in the sample.
Example: Mass, Volume, Calories
2. Intensive - depends on the type of matter, not the amount present
Example: Hardness, Density, Boiling Point

Properties are...
*Words that describe matter (adjectives)
1. Physical Properties - a property that can be observed  and measured without changing the material's composition.
Examples: color, hardness, melting point, boiling point

2. Chemical Properties - is a property that can only be observed by changing the composition of the material.
Examples: ability to burn, decompose, ferment, react with, etc.

STATES OF MATTER
1. Solid - matter than can not flow (definite shape) and has definite volume.
2. Liquid - definite volume but takes the shape of its container (flows).
3. Gas - a substance without definite volume or shape and can flow.
Vapor - a substance that is currently a gas, but normally is a liquid or solid at room temperature.
4. Plasma - formed at high temperatures; ionized phase of matter as found in the sun.
5. Bose-Einstein Condensate - particle to particle

PHYSICAL CHANGE vs. CHEMICAL CHANGE 
1. Physical Change - change the visible appearance without changing the composition of the material.
Ex. boil, melt, cut, bend, split, crack
*can be reversible and irreversible
2. Chemical Change - a change where a new form of matter is formed.
Ex. rust, burn, decompose, ferment, react with
*irreversible

PHASE
*The term "phase" is used to describe any part of a sample with uniform composition of properties.
A homogeneous mixture consists of a single phase.
A heterogeneous mixture consists of two or more phases.

Mixtures are a physical blend of at least two substances; have variable composition. They can be either:
a. Heterogeneous - the mixture is not uniform in composition
ex. chocolate chip cookie, gravel, soil
b. Homogeneous - same composition throughout; called Solution
ex. cool aid, air, salt water
*Every part keeps it's own properties. 

Solutions are homogeneous mixtures
*Mixed molecule by molecule, thus too small to see the different parts
*Can occur between any state of matter: gas in gas, liquid in gas, gas in liquid, solid in liquid, solid in solid (alloys), etc.
*Thus, based on the distribution of their components, mixtures are called homogeneous or heterogeneous.

Separating Mixtures
*Some can be separated easily by physical means: rock and marbles, iron filings and sulfur (use magnet)
*Differences in physical properties can be used to separate mixtures.

Separation of a Mixture
Filtration - separates a solid from the liquid in a heterogeneous mixture by size
Components of dyes such as ink may be separated by Paper Chromatography.

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