Chapter 2 Matter and Change . 2.4 Chemical Reactions 2.1 Properties of Matter 2.2 Mixtures 2.3 Elements and Compounds 2.4 Chemical Reactions Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

State of Matter Depends on: Kinetic Energy – movement of particles States of Matter State of Matter Depends on: Kinetic Energy – movement of particles (temperature) Intermolecular Forces – forces between molecules Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Solids Definite shape and volume. States of Matter Solids Definite shape and volume. Shape does NOT depend on shape of container. Particles packed tightly together. Almost incompressible. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Liquids Particles close together, but NOT rigid or orderly. States of Matter Liquids Particles close together, but NOT rigid or orderly. Indefinite shape because particles are free to flow. Volume is fixed. Almost incompressible. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Takes shape and volume of container. Particles are far apart. States of Matter Gases Takes shape and volume of container. Particles are far apart. Easily compressed. https://www.youtube.com/watch?v=jKMNSvpB9dY Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Physical Change Chemical Change Causes properties of a material to change, but the composition of the material does not. Breaking Change that causes one material to change into a different material. Burning Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Mass of reactants = Mass of Products Chemical Changes A chemical change is also called a chemical reaction. 4Fe + 3O2  2Fe2O3 Reactants  Products Mass of reactants = Mass of Products https://www.youtube.com/watch?v=FofPjj7v414 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Signs of a Chemical Change Transfer of energy Color change Recognizing Chemical Changes Signs of a Chemical Change Transfer of energy Color change Production of a gas Formation of a precipitate. Only way to know for sure is to test composition before & after!!! Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Transfer of energy

Color Change Color Change When a test strip is dipped in a solution, the color change is used to determine the pH of the solution.

Production of a Gas Production of a Gas Bubbles of carbon dioxide form when two antacid tablets are dropped into a glass of water.

Precipitate Formation In the production of cheese, a reaction causes milk to separate into solid curds and liquid whey

Physical Change Chemical Change Change that causes the properties of a material to change, but the composition of the material does not. Examples: Cutting Melting Freezing Change that causes one material to change into a different material. Examples: Burning Rotting Reacting Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Describing Matter Chemical Property – characteristic that can only be observed when we attempt to change the identity of a material Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Physical or Chemical Property? Blue Color Density Flammability Melting Point Reacts with acid to form Hydrogen Burns Boiling Point Hardness Luster (shininess)

Physical or Chemical Property? Blue Color - physical Density - physical Flammability - chemical Melting Point - physical Reacts with acid to form Hydrogen - chemical Burns - chemical Boiling Point - physical Hardness - physical Luster (shininess) - physical

END OF 2.4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .