1.1 MATTER : DEFINITION AND CLASSIFICATION

Classification of Matters with Examples

Matter is a term used for everything having mass and volume. In this unit we will deal with types of matters. Pure substance, elements, compounds, mixtures are subjects of this unit.

1) Pure Matter: Same types of atoms or molecules comprise pure matters. They have some distinguishing properties. There are two pure matters, elements and compounds. Iron, alcohol, salt are examples of pure matters.

Properties of Pure Matters:

• They are homogeneous.
• They have specific physical properties like boiling point, density or freezing point.
• Temperature during phase change is constant

Now we explain pure substances one by one.

a) Elements: Element is the simplest matter which contains one type of atom. There are 109 known element in nature. We show elements with symbols like for iron we use "Fe".

Carbon "C"

Beryllium "Be"

b) Compounds: Two or more than two elements come together in specific amounts and form new matter that we call compound. Properties of compounds are totally different from elements comprising it. We show compounds with formulas like water H₂O. Ions or molecules can produce compounds.

Salt "NaCl"

Ammonia "NH₃"

Iron III Oxide "Fe₂O₃"

Properties of Compounds:

• All compounds are pure substances
• Smallest particle of compound is molecule including different types of atoms

2) Mixture: Different two or more than two types of matter (element, molecule, compound) are mixed to get mixture. All matters forming mixture keep their original properties. They are not pure matters. We can explain mixtures under two titles, homogeneous mixtures and heterogeneous mixtures.

a) Homogeneous Mixtures: All parts of mixture show same properties in homogeneous mixtures. We can call homogeneous mixtures as solutions. Salt water, sugar water, air are examples of homogeneous mixtures.

b) Heterogeneous Mixtures: Mixtures do not show same uniformity in all parts of it. In this types of mixtures, you can see different phases of matters. Water+Sand, milk, blood, soil are some common examples of heterogeneous mixtures.

Emulsion: Heterogeneous mixture including two different liquids. For example, oil-water, gasoline-water are emulsion examples.

Suspension: Heterogeneous mixture produced by one solid and one liquid matter.Sand-water, naphthalene-water are examples of suspension.

Colloids: are heterogeneous mixture type. Solute matters are homogeneously distributed in  solvent however; we can see particles of solute with naked eye or microscope in colloids but, in solutions we can not see particles with microscope. Thus; colloids are assumed to be heterogeneous mixture.

Example: Which one of the following is heterogeneous mixture?

I. Coke

II. Sea Water

III. Water+Sand

IV. Natural Gas

Coke, sea water and natural gas are homogeneous mixture but water sand is heterogeneous mixture.

Differences between Compounds and Mixtures

1. Ratio between matters forming compound is constant but ratio between matters forming mixture is variable.
2. Matters forming compounds loose their properties but matters forming mixtures preserve their properties.
3. We can decompose compounds with chemical methods but decompose mixtures with physical methods.

EXERCISES CLASSIFICATION OF MATTER

Q1.

Material	Pure Substance or Mixture	Element, Compound, Homogeneous, Heterogeneous
sugar + pure water (C12H22O11 + H2O)
Iron (Fe)
limestone (CaCO3)
orange juice
Pacific Ocean
air inside a balloon
aluminum (Al)
magnesium (Mg)
acetylene (C2H2)
tap water in a glass
pure water (H2O)
chromium (Cr)
salt + pure water (NaCl + H2O)
benzene (C6H6)
baking soda (NaHCO3)

Q2.

Classify each of the following as elements (E), compounds (C) or Mixtures (M).  Write the letter X if it is none of these.

1. Diamond(C)                     

2. Sugar (C6H12O6)             

3. Milk            

4. Iron (Fe)

5. Air                          

6. Sulfuric Acid (H2SO4)    

7. Gasoline               

8. Electricity

9. Krypton (K)           

10. Bismuth (Bi)                  

11. Uranium (U)      

12. Popcorn

13. Water (H2O)       

14. Alcohol (CH3OH)          

15. Pail of Garbage 

16. A cat

17. Ammonia (NH3)

18. Salt (NaCl)                     

19. Energy                

20. Gold (Au)

21. Wood                  

22. Ink                                   

23. Pizza

24. Dry Ice (CO2)     

25. Baking Soda (NaHCO3)          

26. Titanium (Ti)      

27. Concrete

Q3.

Read the following information on elements, compounds and mixtures.  Fill in the blanks where necessary.

Elements (pure substances):

1.      A pure substance containing only one kind of _______1_____.

2.      An element is always uniform all the way through (homogeneous).

3.      An element _______2______ be separated into simpler materials (except during nuclear reactions).

4.      Over 100 existing elements are listed and classified on the _________3_______.

Compounds (pure substances):

5.      A pure substance containing two or more kinds of ______4_________.

6.      The atoms are _________5________ combined in some way.  Often times (but not always) they come together to form groups of atoms called molecules. 

7.      A compound is always homogeneous (uniform).

8.      Compounds __________6_________ be separated by physical means.  Separating a compound requires a chemical reaction. 

9.      The properties of a compound are usually different than the properties of the elements it contains. 

Mixtures:

10.  Two or more ________7________ or ________8________ NOT chemically combined.

11.  No reaction between substances.

12.  Mixtures can be uniform (called ____________9____________) and are known as solutions.

13.  Mixtures can also be non-uniform (called __________10______________).

14.  Mixtures can be separated into their components by chemical or physical means.

Classification of Matter