World of Chemistry Chapter 2 Matter Unit 2 Matter World of Chemistry Chapter 2 Matter

Chapter Objectives: Identify the composition of matter Distinguish between elements, compounds, and compounds Define the three states of matter Distinguish between physical and chemical properties Distinguish between physical and chemical changes Distinguish between mixtures and pure substances Identify methods to separate mixtures

What is matter? Matter: anything that mass and occupies space (volume) Matter is classified into two categories: 1. Pure substance: a substance that is composed of one type of element or compound; cannot be separated (aluminum foil, water) 2. Mixture: a substance that is composed of two more elements or compounds; can be separated (Ex.brass, Gatorade)

Pure Substance (Liquid water) Mixture (salt water = NaCl in H2O)

What is matter? Element: a substance made with only one type of atom (H, He, Li, etc.) Atom: the smallest form of an element that retains its chemical properties; tiny particles Molecule: a combination of two or more atoms (O2, H2, H2O, CH4) Compound: a substance composed of two or more different atoms (CH4, AlCl3)

Element Atom 24K gold is a pure substance. It is made of only gold atoms

Molecules and Compounds Cl Cl chlorine, Cl2 S penicillin,with carbon, nitrogen, sulfur, oxygen, hydrogen atoms O O sulfur dioxide, SO2

Types of Mixture Homogeneous (solution): a mixture that has a uniform appearance Ex’s: salt water, brass (alloy), air Alloy: a mixture of metal elements Heterogeneous: a mixture that contains regions with different physical properties Ex’s: dirt, vegetable soup, oil/water

Identifying the following mixtures as homogeneous or heterogeneous

Physical vs. Chemical Physical property: characteristics that describes a substance color, odor, texture, taste mass, volume density, boiling point, melting point physical state (gas, liquid, solid) Physical change: change in one or more physical properties without changing its chemical composition

Physical Examples Physical properties Physical changes bubblegum has a pink color carbon monoxide is odorless the density of water is 1.0g/mL Ms. Cipolla is 1.54m Physical changes cutting wood breaking glass melting silver boiling water

Physical vs. Chemical Chemical property: characteristics that describe how a substance will change into a new substance flammability, radioactivity, oxidizes reactivity with water, acids, bases, air Chemical change: change that occurs when a substance turns into a new substance with different physical and chemical properties

Chemical Examples Chemical properties Chemical changes potassium violently reacts in water silver tarnishes in air hydrogen gas is produced from zinc in acid uranium-235 decay Chemical changes lighting a match photosynthesis baking bread bleaching clothing

States of Matter Matter exists in one of three states (or phases): Solid – rigid, fixed shape and volume Liquid – fluid, no defined shaped, fixed volume Gas – random motion, no defined shape or volume State changes: Use buckmisterfullerene for solid, one in a million container for liquid, and ping pong balls in container for gases

Separating Mixtures Various techniques can be used to separate mixtures: Distillation: used to separate substances in a solution based on differences in boiling point Filtration: used to separate solid substances from a mixture Magnetization: used to separate based on magnetic properties

condenser vapor liquid solution separated material Distillation – a liquid solution is heated. Components are separated out when the temperature reaches their individual boiling point. These now gases cool off as they pass through a condenser and turn back into a liquid where they are collected in a separate container.

Filtration – a heterogeneous mixture (usually composed of a liquid and solid) is passed through a filter, i.e. paper. Material that is small enough to pass through the filter is collected in a separate container.