Chapter 1: Sections 1.1 and Chapter 2: Sections 2.1, 2.2 & 2 .9 Classification of Matter Review: (Mostly on your own) Physical States of Matter Solid Definite volume and shape. Crystalline Internal geometric structure is regular and repeating. Salt, sugar, quartz. Amorphous Internal structure has no regular pattern. Plastic, glass. Liquid Definite volume but indefinite shape. Gas Indefinite volume and indefinite shape. Movement of Particles As you heat a substance, its particle move faster. Particles in the gas phase are moving the fastest. Liquid phase particles move with less energy than the gas phase. Solid phase particles are the slowest but they also have movement. (vibrations). Substance A particular type of matter with a definite, fixed composition. Material that contains only one substance is either an element or a compound. Material that contains more than one substance is a mixture. More on mixtures later. Elements Elements are the most basic form of matter. Cannot be broken into simpler substances by chemical or physical processes. A sample of an element contains only one type of atom. There are over 100 known elements. oxygen, carbon, iron, gold, helium, neon, sodium.. Symbols: O, C, Fe, Au, He, Ne, Na... Some elements come as a couple! We call them “diatomics”: H2, N2, O2, F2, Cl2, Br2, I2 Know these. The elements are listed on the Periodic Table. The Periodic Table Elements are arranged in the periodic table according to their properties. Each element has an “Atomic Number”. Metals are on the left, non-metals are on the right, metalloids between. Compounds Pure substance composed of 2 or more elements. More than one type of atom chemically bonded together. Elemental composition always the same. Law of Constant Composition Molecules Water H2O 2 H atoms, 1 O atom Carbon dioxide CO2 Sugar, sucrose C12H22O11 Salts (ionic compounds) Table salt, sodium chloride NaCl Calcium nitrate: Ca(NO3)2 Types of Matter: Mixtures Most things are composed of more than one type of substance. We call these mixtures. In a mixture, each substance retains it chemical and physical properties. Examples of mixtures: A glass of tap water. A cake. Laundry detergent. Wood. Hair. Air. More on Mixtures Mixtures may be difficult to study because they are composed of more than one substance. They may not have “constant composition” A sample of tap water from my house may contain substances that a sample from your house does not. However, in a mixture, each substance retains its own identity so we may be able to separate the components. Heterogeneous and Homogeneous Mixtures Heterogeneous Distinct regions with definite boundaries. May have multiple phases Wood, orange juice Homogeneous Solution No distinct regions, everywhere the same. Same phase Salt water, air Compounds and Mixtures are Different In a mixture the substances are not bonded together and they retain their individual characteristics. In a compound, the elements no longer retain their individual properties. To separate the elements in a compound you must use a chemical reaction of some type. Mixtures can be separated by physical means. Evaporation, filtration, etc. Physical and Chemical Properties A substance’s physical properties describe how it looks, feels, tastes, how heavy it is, etc. A substance’s chemical properties describe how it reacts with other substances in chemical reactions. Physical Properties of Water Transparent Colorless Boiling Point 100°C (212°F) Freezing Point 0°C (32°F) Density 1.0 g/mL Physical Changes When a substance undergoes a change without changing its chemical nature, this event is called a physical change. Phase changes: Melting, freezing, boiling, etc. Change of form: Crushing salt into a powder. Pounding metal into a sheet. Some Chemical Properties Propane gas is flammable. Iron has the tendency rust. Protein can be digested by enzymes in the stomach. Chemical Changes (Processes) When a chemical reaction happens, chemical change occurs. When iron rusts, iron atoms react with oxygen to form iron oxide. When propane burns, it reacts with oxygen to form carbon dioxide and water. Properties Intensive Does not depend on the amount of substance studied. Density, boiling point, etc. Can be used to help identify a substance. Extensive Depends on the amount of substance present. Pressure, mass, etc. Homework You should know (memorize) the names and symbols of the following elements : Elements #1-20 (don’t memorize their numbers!). Cr, Mn, Co, Ni, Fe, Cu, Zn, As, Br, Ag, Sn, I, Ba, Au, Hg, Pb, U. Ch 1 starts on p. 35 #2 – 7, 21 Ch 2 starts on p. 35 #1 – 10, 20 – 25, 116 – 120