NOTES Physical and Chemical Copyright Houghton Mifflin Harcourt

NOTES: Physical and Chemical Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter LESSON 2 Properties of Matter Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter Physical Properties of Matter • A characteristic of a substance that can be observed without changing the identity of the substance is called a physical property. • You use your senses to observe physical properties. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter What are physical properties of matter? • Mass • Volume • Density • The state of matter (solid, liquid, gas) Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter What are physical properties of matter? • Electrical conductivity - how well electric currents moves through it. • Thermal conductivity – how well it transfers heat. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter What are physical properties of matter? • Solubility - the ability of a substance to dissolve in another substance. • Malleability - the ability of a substance to be rolled or pounded into various shapes. • Ductility – the ability of a substance to be pulled into a wire. • Magnetic Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter What are physical properties of matter? • Luster – shine. • Melting Point - the temperature at which it changes from a solid to a liquid. • Boiling point - the temperature at which a substance boils. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter Chemical Properties of Matter • A chemical property is the ability of a substance to change into a new substance with different properties. • Chemical properties can be identified by the changes they produce. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Properties of Matter What are chemical properties of matter? • Flammability - the ability of a substance to burn. • Reactivity - the ability of a substance to interact with another substance and form one or more new substances. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes LESSON 3 Physical and Chemical Changes Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Physical change: a change that affects one or more physical properties of a substance. • appearance • shape • size • change in state (solid, liquid, gas) • texture Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical change: the process in which one or more substances change into entirely new substances. Chemical changes are not the same as chemical properties. Example: Burning is a chemical change; Flammability is a chemical property. When particles and chemical bonds that make up a substance are rearranged, a chemical change has taken place. Chemical changes can be influenced by temperature. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes How can you tell a chemical change has happened? Signs of a chemical change: • Odors • The production of gas (fizzing, foaming) • A precipitate forms (a precipitate is a solid that falls out of solution) • Energy changes (heat, sound, light) • Changes in temperature • Changes in color Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical Reactions Substances used in a reaction are called reactants. After the reaction is complete, the new substance that formed is called the product. During a chemical reaction bonds between reactants are broken down and new bonds are formed in the products. Example: 2 Hydrogen (H) + Oxygen (O) Water (H 2 O) [-----Reactants-----] [--Product--] Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical Reactions Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical Reactions Activation energy is the energy required to get a chemical reaction started. EXAMPLEWhen baking cookies the oven provides activation energy Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical Reactions Exothermic Reaction – energy is released and temperature increases. Energy can be released in two general ways light and heat. EXAMPLE *CH 4 + 2 O 2 - CO 2 + 2 H 2 O + 890. 4 KJ *All combustion reactions are examples of exothermic reaction. -Exothermic Reactions are symbolized as: reactants - Products + energy Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Physical and Chemical Changes Chemical Reactions Endothermic Reaction – energy is absorbed and temperature decreases. Endothermic reactions will cool the area around them by absorbing the necessary energy from the surroundings, decreasing the temperature. EXAMPLES * Chemical cold packs are examples of endothermic reactions. * photosynthesis, where plants absorb energy as sunlight to turn carbon dioxide and water into glucose and oxygen. -Endothermic Reactions are symbolized as: Reactants + energy Products Copyright © Houghton Mifflin Harcourt Publishing Company