PROPERTIES OF PURE SUBSTANCES What is a pure

PROPERTIES OF PURE SUBSTANCES What is a pure substance? Non-characteristic properties Characteristic properties (physical and chemical) Determining an unknown substance

What is a Pure Substance? � Substance made up of 1 type of atom OR 1 type of molecule � Mixtures are NOT pure substance � 2 types ◦ Elements � 1 type of atom �Iron, oxygen, ◦ Compounds �At least 2 types of atoms �Water, salt,

Non-Characteristic Property �A property that is shared by many substances � It does not allow you to identify it � Examples: mass, volume, temperature, color, shape.

Characteristic Property �A property that is unique to that one substance � Allows you to identify it right away � Examples: DNA, boiling point, density

Physical Characteristic Properties � Once the observation of the property is made, the molecular make-up of the substance remains the same � Examples: melting point, boiling point, density, solubility � See Table 1. 30 on page 23 of textbook

Chemical Characteristic Properties � Once the action or observation is made, the substance is no longer the same, its molecular make-up has changed � Examples: burning, digesting, use of indicators � See Table 1. 31 on page 24 of textbook

Determining an Unknown Substance � There are many tests that can be done to identify a substance which include: ◦ Conductivity: if light of conductivity meter comes on ◦ Malleability: ability to bend ◦ Magnetism: substance is attracted or repelled by a magnet ◦ Smell ◦ Colour ◦ Metallic luster: shine, all metals shine ◦ Density ◦ See tables on pages 23 and 24 of textbook