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Ms. Neuner's Science Classes

Chemistry Honors
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Chemistry Honors
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Class Notes from 9/8-9/16
 
Matter: anything that has mass and volume
Mass: the amount of material in an object
lUsually measured in grams
Volume: the amount of space taken up by an object
lUsually measured in liters
 
Therefore, matter is anything that contains material and takes up space
 
Two pieces of matter cannot exist in the same space

Types of Matter
 
 
1. Elements
lCannot be broken down into simpler parts by chemical means
l118 different elements
 
2. Compounds
lCan be broken down into simpler parts by chemical means
lMany different compounds

Mixtures
 
 
Mixtures are always composed of two or more pure substances
Some characteristics of mixtures:
l1.  The substances can be elements or compounds
l
l
 
2.  The ratio of the components of the mixture are not fixed
lCan contain as much of substance A and B as you want
 
3.  The properties of a mixture are always mid-way between those of its components
l If A boils at 100C, and B boils at 50C, the mixture will boil around 75C
l
l
 
4.  A mixture can be homogeneous or heterogeneous

 
Homogeneous: the mixture is the same no matter where you look
lAlso called a solution
lEx: iced tea mix in water
 
Heterogeneous: the mixture is different in different areas
lEx: collection of pens

Separating Mixtures
 
Mixtures can be separated based on the properties of the individual components
 
Some properties are:
lDensity: the substances float at different levels
lPolarity: one substance is attracted to positive charges, while the other is attracted to negative charges
lFreezing point: one substance will freeze before the other
lBoiling point: one substance will boil off before the other

Filtration
 
 
Useful if the mixture is made up of a solid in a liquid
 
If left alone, the solid will settle to the bottom of the container
 
You can carefully pour off the liquid (decanting) 
 
A filter is a material that allows small particles to pass through, but traps larger particles
lContains holes of a certain size
lOnly particles smaller than the holes pass through
Liquid passes through the filter, but solids get stuck

 
Brita water filter takes solids out of water
Air conditioners have filters that remove dust from the air

 
If the mixture is homogeneous, distillation can be used
If the mixture is made of a solid and a liquid:
lThe liquid heats until it becomes steam
lThe steam is quickly cooled and collected as distillate
lThe solid remains in the flask
l Ex: salt water
 
 
If the mixture is made up of two liquids that combine, the liquids are miscible
lThe liquid with the lower boiling point is collected as the distillate
lEx: alcohol and water
 
 
Chromoatography
 
Used to separate components of a mixture that have different attractions for other substances
 
Different components move at different speeds through the material

 
If the mixture is made up of two liquids that combine, the liquids are miscible
lThe liquid with the lower boiling point is collected as the distillate
lEx: alcohol and water

Chromoatography
 
 
Used to separate components of a mixture that have different attractions for other substances
 
Different components move at different speeds through the material

Phases of Matter
 
Matter has three different phases:
l1.Solid
l2.Liquid
l3.Gas
 
Solids
 
Contains matter that is held in a rigid form
 
Has a definite volume and shape
 
Particles are held in fixed locations by strong attractive forces
 
True solids have a crystalline structure
 
Liquids 
 
Particles are not held together as rigidly as those in solids
 
Particles are able to move past each other
 
No definite shape, but has a definite volume
 
Takes the shape of its container
 
Gases
 
Particles are barely held together
 
Particles can move wherever they want, unless confined in a container
 
No definite shape or volume
 
 

St. Edmund Preparatory HS Science