1. Classification of Matter Notes

2. Matter Matter is anything that has volume & mass (including gasses).
Things that are not made of matter include fire, light, gravity, sound, and heat.

3. All matter is classified as a pure substance or a mixture based on its composition.

4. What qualifies something as a pure substance?
A pure substance has a fixed composition.
Pure substances are made of a single repeating particle- either an element or a molecule- with nothing else mixed in.
Pure substances are either compounds or elements.
They cannot be separated into its components by any physical processes

5. What Classifies something as an element?
An element is a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom.
There are over 100 elements, all listed on the periodic table.
An atom is the smallest unit of an element that maintains the chemical identity of that element.

6. What classifies something as a compound?
A compound is a substance that can be broken down into simple stable substances through chemical reactions.
A molecule is the smallest unit of an compound made from two or more bonded atoms in a fixed composition.
The composition of a compound is represented by a chemical formula.
Compounds are held together by chemical bonds

7. How are elements different from compounds?
Elements are composed of only one type of atom
Ex. Si, O2
They usually do not have a chemical bond, unless the element is diatomic, which means it only exists in nature as a pair
Compounds are composed of more than one type of atom
Ex. SiO2
They must have at least one chemical bond

8. How do the properties of elements change when they become compounds?
The properties of compounds are quite different from those of their component elements.
When the elements sodium and chlorine combine chemically to form sodium chloride, there is a change in composition and a change in properties.
Sodium is a soft gray metal that is explosive when placed in water
Chlorine is a pale yellow poisonous gas.
Sodium chloride (commonly known as table salt) is a white solid.

9. What qualifies something as a mixture?
A mixture is a blend of two or more kinds of matter, each of which retains its own identity and properties.
mixed together physically
can usually be separated physically
composition is not uniform
has no chemical formula

10. Types of Mixtures Homogeneous mixtures are called solutions
uniform in composition (salt-water solution)
does not look like a mixture
Heterogeneous mixtures
not uniform throughout (sand-water mixture)
the mixtures components are visible

11. Homogeneous vs. Heterogeneous

12. Solution a homogeneous mixture can be physically separated
composed of solutes and solvents
Water is considered the universal solvent as it is the solvent used to sustain all life
the substance in the smallest
amount and the one that dissolves in the solvent
the substance in the larger
amount that dissolves the solute
Iced Tea Mix
(solute)
Iced Tea
(solution)
Water
(solvent)

13. Solutes Change Solvents
The amount of solute in a solution determines how much the physical properties of the solvent are changed
Examples:
Lowering the Freezing Point
Raising the Boiling Point
The freezing point of a liquid solvent
decreases when a solute is dissolved in it.
Ex. Pure water freezes at 00C, but when salt is
dissolved in it, the freezing point is lowered.
This is why people use salt to melt ice.
The boiling point of a solution is higher
than the boiling point of the solvent.
Therefore, a solution can remain a liquid at
a higher temperature than its pure solvent.
Ex. The boiling point of pure water is 1000C,
but when salt is dissolved in it, the boiling
point is higher. This is why it takes salt water
longer to boil than fresh water.

14. Concentration
the amount of solute dissolved in a solvent at a given temperature
described as dilute if it has
a low concentration of
solute
described as saturated if it
has a high concentration of
described as supersaturated if
contains more dissolved solute
than normally possible

15. Solubility
The ability of a solute to be able to dissolve in a solution
The more soluble a substance is, the greater the concentration the solution is capable of having
Influenced by:
Temperature
Pressure
Solids increased temperature causes
them to be more soluble and vice versa
Gases increased temperature causes
them to be less soluble and vice versa
Ex. Iced Coffee
Solids increased pressure has no
effect on solubility
Gases increased pressure causes them
to be more soluble and vice versa
Ex. Soda, “The Bends”