Thursday, September 1, 2016

Types of Matter

Everything is made of matter (and energy) of one kind or another. If you can see, smell, taste, or feel it, it is matter. 

matter 
physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, especially as distinct from energy.

There are two main groupings of matter: pure substances and other substances.

First, we will consider pure substances. Pure substances have the following characteristics:

Matter that has exactly the same composition.

Every sample of a pure substance has the same properties because it has a fixed, uniform composition.

There are two types of pure substances:
  • Elements
  • Compounds

Elements:

Element
each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e., the number of protons in the nuclei of its atoms.

Every sample of an element has the same properties because it has a fixed, uniform composition because an element contains only one type of atom. (An atom is defined by its unique combination of protons, neutrons, and electrons. Protons neutrons, and electrons are the basis for all matter.) No two elements contain the same type of atom.

Key points about elements:
    • All samples of any element share the same properties.
    • Elements have a fixed, uniform composition because they contain only one type of atom.
    • All of the atoms of a given element have a unique combination of protons, neutrons, and electrons.

Compounds:

Compound
a substance formed from two or more elements chemically united in fixed proportions

Every sample of a compound has the same properties because it has a fixed, uniform composition made up of a specific combination of other simpler substances (elements or other compounds) in set, fixed, specific ratios.

The properties of a compound differ from those of the substances from which it is made. For example, water is a liquid at room temperature, but both hydrogen and oxygen are gasses.


Key points about compounds:
    • All samples of any compound share the same properties.
    • Compounds have a fix uniform composition because they are made up of a specific combination of other simpler substances in set, fixed, specific ratios. (For instance water is the compound made up when two hydrogen and one oxygen atoms combine.)
    • The properties of a compound differ from those of the substances from which it is made.
    • A compound always contains two or more elements joined in a fixed proportion.

Because pure substances are joined and defined at the atomic level you cannot physically separate them into anything other than smaller quantities of the same thing. Any subdivision of an element or a compound will have the same properties as the original, but scaled down for size.


Not all matter is classified as a pure substance. There are other types of substances called mixtures.

Mixtures are made up of various substances, but each substance can be separated because they are not bound at the atomic level. (They are not chemically or atomically bonded.)

One analogy for a mixture is a salad. Though tossed together, each part of the salad retains its individual characteristics and identity. All of the tomatoes could be picked out because they are not bound to the other parts of the salad.

Based on how they are put together, mixtures can be classified as heterogeneous or homogeneous.

Heterogeneous mixtures:
  • The parts of the mixture are noticeably different from one another. 
  • The composition is not the same throughout.
  • You CAN divide out different parts…like picking tomatoes out of a salad!

Homogeneous mixtures:
  • The parts of the mixture are not noticeably different from one another. 
  • The composition is the same throughout.
  • You CANNOT divide out different parts. It’s like salt water.
  • The substances are so evenly distributed that it is hard to distinguish one substance in the mixture from another.

Another way to classify mixtures is to look at how they behave under certain conditions. This classifying method mostly relates to mixtures involving fluids (liquids and gasses).

Mixtures can be classified as solutions, suspensions, or colloids.

Solutions:

Solution
a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

SOLVENT: the major component in a solution
SOLUTE: the minor component in a solution

Key points about solutions:
  • Homogeneous
  • SMALL particles of one substance within another substance.
  • Liquid solutions do not separate into distinct layers.
  • Cannot be filtered into different parts.
  • Does not scatter light.

Suspensions:

Suspension
a mixture in which particles are dispersed throughout the bulk of a fluid

Key points about suspensions:
  • Heterogeneous
  • LARGER particles of one substance within another substance.
  • Liquid suspensions do separate into distinct layers.
  • Can be filtered into different parts.
  • Will scatter scatter light—suspensions are cloudy.


Colloids:

Colloid
a homogeneous, noncrystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

gel: a semisolid colloidal suspension of a solid dispersed in a liquid.

sol: a fluid suspension of a colloidal solid in a liquid

emulsion: a fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible.

Key points about colloids:
  • Homogeneous
  • INTERMEDIATE sized particles of one substance within another substance.
  • Liquid colloids do not separate into distinct layers.
  • Cannot be filtered into different parts.
  • Will scatter scatter light—like fog or milk.


What if?

Milk (a colloid) has salt dissolved into it?

— The saltiness would act like a solution.

Now, mix dirt into the salty milk?

— Now, there is a suspension of dirt in the salty milk!

Conclusion:

The physical universe is composed of matter, and matter can be classified into different types. Understanding what they are, how they are alike, and how they are different is a fundamental part of viewing the universe through the lens of science.

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Definitions and content from:
New Oxford American Dictionary
Physical Science Concepts in Action, Pearson 

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