Unit 1B: Introduction to Chemistry Ms. Wallace General Chemistry

I. Important Terms Chemistry: Matter: The study of matter and its changes Any object that has a mass and volume (pretty much anything)

I. Important Terms Atom: - Particle Diagram: Smallest particle of an element that retains the properties of that element Can not be broken down by a chemical reaction 2 different types of elements

I. Important Terms Compound: - Particle Diagram: Two ore more DIFFERENT ELEMENTS BONDED together Can be broken down by a chemical reaction 1 type of compound

II. Phases of Matter The phases that matter is in depends on: 1. The space between atoms or molecules 2. The strength of the intermolecular force (IMF) between atoms

Takes shape of con-tainer definite Med-ium Vibrate and rotate Phase Shape Volume IMF Movement Solid (s) Liquid (l) Gas (g) definite definite strong vibrate Takes shape of con-tainer definite Med-ium Vibrate and rotate Takes shape of con- tainer Takes shape of con- tainer weak Vibrate and rotate

III. Classification of Matter Element (Column A): Compound (Column B): Mixture (Column C): Substance that cannot be changed into a simpler substance under normal conditions Substance consisting of 2 or more different chemical elements that can be separated by chemical reactions (heat, electricity) A physical blend of 2 or more substances that are NOT chemically combined (air, soup, tap water)

Aqueous Solution (aq): a mixture of water and some other substance that can dissolve in water (salt water) Element Compound Mixture

How Elements, Compounds, and Mixtures can be illustrated N2 (g) CO2 (g) Air (N2, O2, H20, CO2(g)

Cool Animation

IV. Physical vs. Chemical Properties Properties of an element or compound that can be observed or measured WITHOUT a chemical reaction Ability of an element or substance to undergo a chemical reaction (bond breaking) and form a NEW substance

IV. Physical vs. Chemical Properties Color, texture, odor, density, melting/freezing temps, solubility, volume, mass VIDEO EXAMPLE Reactivity, pH (acidity), ability to rust, decompose, ferment, combust VIDEO EXAMPLE

IV. Physical vs. Chemical Properties

V. Physical vs. Chemical Changes A change that does NOT produce a new substance, it just changes the position of the particles Changing a substance into a NEW substance (bonds are broken and then new ones formed) A color change may occur and a NEW s, l, or g is formed A change that does NOT affect a substance’s chemical position

V. Physical vs. Chemical Changes Any phase change (freezing, melting…), dissolving, mixing, cutting Burning, rusting, fermentation, cooking/baking

V. Physical vs. Chemical Changes liquid water freezes to ice salt dissolves in water liquid nitrogen in plastic bottle bursts open rusting on a pan potassium reacting with water to form potassium hydroxide and hydrogen gas 2K (s) + 2H2O (l) -> 2KOH (aq) + H2 (g)

IV. Physical vs. Chemical Properties

A chemical reaction ALWAYS results in a new substance Chemical Reaction Equation: 4 H +2 O 6 Total 4 H +2 O 6 Total = Reactants Products 2 H2 (g) + O2 (g)  2 H2O (l) Coefficient # of atoms A chemical reaction ALWAYS results in a new substance

Mass cannot be created or destroyed in a chemical reaction Conservation of Mass: Mass cannot be created or destroyed in a chemical reaction The total mass of reactants equals the total mass of the products Example (video clip) Silver nitrate (AgNO3) and sodium chloride (NaCl) solutions before and after mixing

Examples: 50 g + Sodium+ 76 g 126 g Sodium Chloride Chlorine  1) If 50.0 grams of sodium reacts with chlorine to form 126 grams of sodium chloride. How many grams of chlorine reacted?   2) If 178.8 g of water is separated into hydrogen and oxygen gas, and the hydrogen gas has a mass of 20.0 g. What is the mass of the oxygen gas produced? 50 g + Sodium+ 76 g 126 g Sodium Chloride Chlorine  178.8 g  H2O  20 g + 158.8 g H2 + O2

Definite Composition (Homogeneous) VI. Classification of Matter Chart Matter Substance Definite Composition (Homogeneous) Physically Separable Mixture of Substances

Nonuniform; distinct phases VI. Classification of Matter Chart Mixture of Substances Homogeneous Uniform throughout (air, tap water, gold alloy, salt water, Kool-Aid) AKA – SOLUTIONS Heterogeneous Nonuniform; distinct phases (soup, concrete)

Water (H2O), Carbon Dioxide (CO2) VI. Classification of Matter Chart Substance Element Iron, Sulfur, Oxygen Compound Water (H2O), Carbon Dioxide (CO2) Chemically Separable