UNIT III Lesson 2Classification of Matter

Classification of matter

SOME DEFINITIONS TO KNOW

A system: a part of the ________ being studied in a given situation.

A phase: part of a _______ which is uniform in both composition and properties.

Phases in a particular system are distinct____________ separated from each other by _______________ ( sometimes we use a microscope to see these boundaries).

III.3 CLASSIFICATION OF MATTER

Atom: The smallest part of an element which retains ALL the fundamental properties of the element…Elements - contain only one type of atom

1. monatomic elements consist of 1 atom only ex: Fe, Al, Cu, He2. polyatomic elements consist of several “like” atoms bonded together Ex: H2 O2 Br2 F2 I2 Cl2 P4

III.3 CLASSIFICATION OF MATTER

A molecule is 2 or more atoms held together

If a molecule is made up of identical atoms, it is called an element.

If a molecule is made up of different atoms, it is called a compound.

Atoms are held together by electrical forces.

III.3 CLASSIFICATION OF MATTER

Difference between an element and a compound?

First, they are both molecules (2 or more atoms)

An element is made up of the same type of atoms

A compound is made up of different types of atoms.

III.3 CLASSIFICATION OF MATTER

ION: atom or molecule that possesses an electrical charge…

Sodium ion (Na+ ) Chloride ion (Cl- ) Nitrate ion or Nitrate ( NO3

- )

A particle: general term to describe a small bit of matter like atom, molecule, or ion.

MORE TERMS TO CLASSIFY MATTER

Pure substance: unchanged, uniform properties. Ex: salt (NaCl) has a density of 2.16 g/mL and

melts at 801 C and is colourless. It is homogenous in composition too!

Homogenous: consisting of only one phase.Ex: air, water, a piece of iron

Heterogeneous: consisting of more than one phase.

Ex: human beings, pencil, gravel.

2 TYPES OF MIXTURES

A mixture: a system made up of 2 or more substances, and the amounts can be different/varied.

Ex: salt dissolved in water.

If a mixture is heterogeneous, it is called a mechanical mixtureEx: sand, iron filings with sulphur

MIXTURE OR COMPOUND VIDEO …

Iron filings and sulphur

http://www.youtube.com/watch?v=cL6I1O1YHH0

2 TYPES OF MIXTURES If a mixture is homogenous, it is called a solution.

gas-in-gas our air (hydrogen, oxygen, nitrogen)

gas-in-liquid soda, pop cans.

liquid-in-liquid alcohol and water

THEY LOOK LIKE THERE ARE ONE THING…

Homogeneous solution

Heterogeneous solution

Clear solution. Transparent and will not settle

Translucent or opaque solution may settle in some cases

Solutes and solvent cannot be separated by filtration or a

magnet

Can be separated by filtration or a magnet

Salt water, air, alloys Smoke, milk, muddy water

PAGE 50: CLASSIFYING SUBSTANCES SCHEME*

III.3 CLASSIFICATION OF MATTER

A solution is a homogeneous mixture of 2 or more substances

A solvent: the component in a solution that exists in greater amounts.

A solute: the component in a solution that exists in lesser amounts

III.3 CLASSIFICATION OF MATTER

III.3 CLASSIFICATION OF MATTER

*Aqueous solutions are solutions where the solvent is water. The subscript (aq) indicates that a compound is in aqueous solution.

* When water exists in solution, we call water the solvent EVEN if it exists in LESSER quantity.

HomeWork for Monday ( for marks ) QUESTIONS: p. 52 #33 - 44