The Classification of matter

1.Before we classify matter, we should know:

Basically, people classify matter according to their physical properties.

Any part of the universe that is being studied in a given situation is a SYSTEM. Inside a system, means matter that have the same chemical and physical properties evenly is a PHASE.
external image stock-photo-colorful-cocktail-isolated-on-black-35901862.jpg→ 【1】Two phases are contained in this cup of drink,because the drink inside have two colours and they have a clear distinction. One is in colour red and the colour is very bright while the other one is in colour yellow and it looks cloudy.

Matter are made by particles such as atoms (the smallest possible unit of an element which remains the properties of the element), molecule (a group of two or more kinds of atoms held together by electrical forces) or ion.

These fundamental parts of the world are important in classifying matter.

2. Two ways of classification:

1)In our textbooks,the author classify things according to their phases

All substances can be divided into two categories:
1.Homogeneous substances
2.Heterogeneous substances

Heterogeneous substances are multi-phases substances, it means they have more than one phase. Contrary to this, homogeneous substances are substances with only one phase.


【2】This's a photo of the chart on the text book

Homogeneous substances can be divided into pure substances (can be written in a chemical formula and have unchange properties) and homogeneous mixture which has variable composition.

【3】This is a picture from It presents a homogeneous matter inside, because the cup only have one phase inside.

If there is only one kind of atom presented in the pure substance, we consider it as an element. Because the definition of
element is any substances that can not be seperated into simpler form by chemical process.
For example: A pure piece of iron can be written as Fe and there's only one kind of atom presented in this substance.
iron.jpg→【4】This is a picture from, it's an example of an element Fe.

f more than one type of atom is presented in the pure substance, it is considered a compound. Because a compound is a pure substance made of 2 or more types of atoms. However, only one type of molecule is presented in a compound.
For example: Pure water is H2O and there is only one molecule presented in the sustance.
water.jpg→【5】A picture from, it shows the structure of a compound.

f a substance is homogeneous, but more than one kind of molecule in it, we classify it as a solution.The definition of a solution is a homogeneous mixture of two or more substances. A solution does not need to be a liquid!!
stainless_steel_ball.jpg →【6】A Stainless steel is a group of iron-based metal containing at least 10% alloy metals. It is homogeneous and it has more than one kind of molecule in it. Therefore, it is a kind of solution.

If the substance has more than one phase, we classify it as a
heterogeneous substance and because it's a mixture of two or more substances, we consider it as a mechanical mixture.

pizza.jpg →[8]This is an example for mechanical mixture.

In conclusion, when there is a substance need to be classified
1. State it's homogeneous or heterogeneous substance.
2. If it is a heterogeneous mixture, it's a mechanical mixture.
3. If it is a homogeneous mixture, try to write it's chemical formula.
4. If it contains variable formulas, it's a solution.
5. If the formula contains a molecule, it's a compound.

6. If the formula contains only one kind of atom, it's an element.

2)Actually, matters can be classified into mixtures or pure substances as well


【7】Thanks to

The advantage of this kind of classification is the differences between pure substances and mixture are showed clearly instead of having mixtures in two branches.

Because we have already understand all the terms, we can directly conclude the process as:
1. Write the chemical formula for the substances.
2. State whether it's a pure matter or a mixture.
3. If it can be written in a chemical formula and the formula contains a molecule, it's a compound.
4. If the formula has only one atom, it's an element.
5. If it's cannot be written in a chemical formula, and it has only one phase, it's a homogenous mixture.
6. If it has more than one phase, it's a heterogenous mixture.

【2】<Hebden: Chemistry 11> by James A. Hebden, Ph.D. P49, P50, P51, P52
g08viiia8fe.htm, it's an example of an element Fe.//
【5】A picture from