Classification+of+matter

= 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. **→ 【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 //** 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. __//
 * All substances can be divided into two categories:

__//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 http://hubpages.com/hub/Heterogeneous-and-Homogeneous-Mixtures. It presents a homogeneous matter inside, because the cup only have one phase inside. **
 * 【2】This's a photo of the chart on the text book**
 * 【2】This's a photo of the chart on the text book**

// For example: A pure piece of iron can be written as Fe and there's only one kind of atom presented in this substance. // ** →【4】This is a picture from http://www.tqnyc.org/2006/NYC063220//g08viiia8fe.htm, it's an example of an element Fe.// ** //  For example: Pure water is H 2  O and there is only one molecule presented in the sustance. // →【5】A picture from http://www.3dchem.com/molecules.asp?ID=234, it shows the structure of a compound.
 * 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.__ //
 * I** // **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.__

**I** // **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!! **  **→【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__.

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

** I **** n 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 http://www.chemistrytutorials.org/index.php/content/matters-and-properties-of-matters/classification-of-matters** // **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. **

//** 3.References: 【1】 ** ** www.shutterstock.com ** ** 【3】http://hubpages.com/hub/Heterogeneous-and-Homogeneous-Mixtures. ** [8] http://www.bcssa.org/newsroom/scholarships/great8sci/Matter/Mixtures/Mechanical.html **
 * 【2】 by James A. Hebden, Ph.D. P49, P50, P51, P52 **
 * 【4】http://www.tqnyc.org/2006/NYC063220 **//**g08viiia8fe.htm, it's an example of an element Fe.//**
 * 【5】A picture from http://www.3dchem.com/molecules.asp?ID=234 **
 * 【6】http://www.lenntech.com/stainless-steel.htm#ixzz0qyykppv9**
 * 【7】http://www.chemistrytutorials.org/index.php/content/matters-and-properties-of-matters/classification-of-matters