Introduction to Chemistry Chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions Matter - anything that takes up space and has mass There are different kinds of matter. Each different kind of matter has different properties

Physical Property of Matter: a characteristic or description of a substance that can be used to identify it. Examples: State of matter (liquid, gas, solid) Hardness Malleability - (how easy to bend) Ductility - (how easy to stretch) Melting/Boiling Point Crystal Form Solubility in Water Viscosity Density

Chemical Property of Matter: a characteristic or behavior that occurs when one substance interacts with another to create a new substance Examples: Combustibility/Flammability Reaction with acids

Gold is very dense. This is an example of one of its ______________ properties Physical Chemical 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Sugar can easily dissolve in water Sugar can easily dissolve in water. This is an example of its ______________ properties Physical Chemical 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Hydrogen gas is explosive. This is one of its ____________ properties Physical Chemical 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Physical Changes A change that does not alter the chemical composition of a material A change in which no new substance is formed Hints 1. Usually reversible 2. Don’t involve changes in color or odor 3. Cutting, grinding, bending, melting, freezing, breaking, cracking, disolving

VAPOR O H H WATER O H H ICE O H H

Chemical Changes A change that produces new substances with new properties Hints 1. Energy is absorbed or given off 2. Changes in color or odor 3. Production of gas or solid from liquid 4. Not easily reversible 5. burn, rust, ferment, rot, decompose, explode

Reactants and Products In a chemical change, the particles you start with are different than the particles you end with The particle you have before the reaction are called reactants The particle you have after the reaction are called Products

Hydrogen Gas Molecule Oxygen Gas Molecule Energy is absorbed Gas from liquid Water molecule

Which of the following is a chemical change? Ice melting into water Sugar dissolving into water Hydrogen burning and turning to water 2 and 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Q2. Which of the following is not a physical property.. smell solubility viscosity They all are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

In a cars engine gasoline combusts and turns into CO2 In a cars engine gasoline combusts and turns into CO2. this is a ___________________ change Chemical Physical both 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Physical or Chemical A. garbage rotting (decomposition) - B. cutting up carrots – C. A silver spoon turning black – D. Making tea from tea leaves – E. Bleaching a stain – F. Boiling an egg - CHEMICAL (new substance) . (odor change) PHYSICAL (still carrots) CHEMICAL (color change) PHYSICAL (still tea just dissolved) CHEMICAL (color change) CHEMICAL (not reversible)