MLS Inorganic & Organic Chemistry Lecture Notes 2.docx

MLS Inorganic and Organic Lecture Notes: Chapter 2: Matter and Energy **Content:** - Classification of Matter - States/Phases of Matter - Properties and Changes of Matter - Fundamental Laws Chemistry is the study of **MATTER:** its structure, composition, properties, and its reactive c...

MLS Inorganic and Organic Lecture Notes: Chapter 2: Matter and Energy **Content:** - Classification of Matter - States/Phases of Matter - Properties and Changes of Matter - Fundamental Laws Chemistry is the study of **MATTER:** its structure, composition, properties, and its reactive characteristics. **1. Classification of Matter** Matter- anything that has mass and occupies space. Typically found in 3 different states: solid, liquid, and gas. Recent discoveries found that there are 2 additional states: Plasma, and Bose-Einstein Condensate. ***1.1 Pure substance:** if the matter has a uniform chemical composition and distinct properties. It can if classified as **Element** if it cannot separated into simpler substance by chemical methods. **Compound** if the matter is composed of 2 or more elements in fixed proportions; can be separated into component elements by chemical means.* ***1.2. Mixture**:* if matter consists of two or more pure substances that retain their identities and can be separated by physical methods. ***Homogeneous*** mixtures are those having a uniform composition and properties throughout i.e. Solutions*.* Solutions are made up of solutes and solvents. Solute is the material present in smaller amount in a solution whereas solvent is the material present in larger amount in a solution. Types of Solutions: ***Heterogenous*** mixtures are those that are not uniform in composition and properties i.e. Colloids and suspensions. Colloids refer to dispersions of small particles from around 1 nm to 10 micrometers.  Suspensions have large solute particles and can be easily seen. It is unstable as it settles down after some time. **Elements:** H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg... **Compounds:** H~2~O, NaCl, CaCO~3~, Na~2~CO~3~, NaOH.. **Solutions:** vinegar (acetic acid in water), alcoholic beverages (ethanol in water), coffee... **Colloids:** refer to table. Liquid aerosol, solid aerosol, emulsions, solid suspensions,... **Suspensions:** muddy water, flour in water, sand particles suspended in water, milk of magnesia **2. States/Phases of Matter** Solid: definite shape and volume, generally cannot be compressed, slight expansion during heating, high density. Liquid: No definite shape as it takes the shape if its container, has definite volume, can be compressed, slight expansion during heating, medium density. Gas: No definite shape and volume. Can be greatly compressed due to large spaces of molecules from each other. Great expansion during heating, low density. Plasma: No definite shape and volume, made up of ions and electrons, often seen in ionized gases. Bose-einstein condensate: No definite shape and volume, made when cloud of boson is supercooled close to absolute zero. **3. Properties and Changes of Matter** Properties of Matter: Physical Properties: Characteristics of a substance that can be observed or measured without changing the identity of the substance. It includes: color, hardness, malleability, solubility, density, melting point and boiling point. Chemical Properties: Refers to the ability of a substance to undergo chemical change. Examples are: Flammability, toxicity, pH level, reactivity and volatility. \*Intensive/Intrinsic properties- Do not depend on the amount of matter being measured. E.g. temperature, color, odor, density. \*Extensive/Extrinsic properties- Depends on how much matter is being consider. E.g. mass, volume Phase changes: Solid-Liquid = Melting Liquid-Solid = Freezing Liquid-Gas = Evaporation Gas-Liquid = Condensation Solid-Gas = Sublimation Gas-Solid = Deposition Gas-Plasma = Ionization Plasma-Gas = Deionization Gas-B.E.C = cooling to near absolute zero **4. Fundamental Laws** **Law of Conservation of Matter**: states that matter cannot be created nor destroyed in a closed system. The mass of the reactants in a chemical reaction must be equal to the mass of the products. Example: Decomposition of Mercuric oxide **Law of Definite Composition**: states that a chemical compound always contains the same proportion of elements by mass, regardless of the sample or source of the compound. Example: Water (H₂O) is a good example of this law: Water always consists of 2 hydrogen atoms and 1 oxygen atom. By mass, water is always about 11% hydrogen and 89% oxygen, whether it's from a lake, ocean, or laboratory. **Law of Multiple Proportions**: states that when two elements combine to form more than one compound, the ratios of the masses of the second element, which combine with a fixed mass of the first element, are in small whole number ratios. Example: Carbon and oxygen can form two compounds: carbon monoxide (CO) and carbon dioxide (CO₂): In carbon monoxide (CO), 12 grams of carbon combine with 16 grams of oxygen. In carbon dioxide (CO₂), 12 grams of carbon combine with 32 grams of oxygen. The ratio of the mass of oxygen in these two compounds is 32:16, or 2:1, which is a simple whole number.