UNIT III Lesson 2 Classification of Matter

Classification of matter

S OME 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, He 2. polyatomic elements consist of several “like” atoms bonded together Ex: H 2 O 2 Br 2 F 2 I 2 Cl 2 P 4

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 types 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 ( NO 3 - ) A particle: general term to describe a small bit of matter like atom, molecule, or ion.

M ORE 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 mixture Ex: sand, iron filings with sulphur

M IXTURE OR COMPOUND VIDEO … Iron filings and sulphur

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 cannot be separated by filtration or a magnet Can be separated by filtration or a magnet Salt water, air, alloysSmoke, milk, muddy water

PAGE 50: C LASSIFYING 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

* 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 #