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Download CHM 115 matter measurement and problem solving part 1
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Matter Measurement and Problem Solving Atoms and Molecules, Inquiry, Classification of Matter, and physical and chemical changes What is chemistry? Studies matter, including changes involving matter and energy accompanying the change The science that seeks to understand behavior of matter by studying behavior of atoms and molecules What is matter? Universe Matter Has massAmount of matter Occupies volume Energy Further classified by state and/ or purity No mass or volume Ability to produce change Further classified by type of change (heat, work, etc.) Atoms vs. Molecules Atom ◦ Most basic unit of matter ◦ Fundamental particles that are the building blocks of ordinary matter Molecule ◦ Atoms are typically not in isolation ◦ Group of atoms that are held together by chemical bonds Scientific Method Variables Math is used in every step of the scientific method- it is a tool of science Independent variable- x axis (set value) Dependent variable- y axis (responds to changes in x) Experiment Allows determination of cause and effect Expressed as math relationship or graph Determining Scientific Theory One or more well-established hypotheses may form basis for scientific theory Scientific Theory vs. Scientific Law Theory- Well tested hypothesis ◦ ◦ ◦ ◦ Best explanation/ model General Can be used to predict Validated by experimentation but can never be conclusively proven Scientific Law – General summary of related observations ◦ Often in form of math relationship ◦ Subject to further verification by experiment ◦ NOTE- scientific law can be proven invalid by new data. (e.g. Law of Conservation of Mass invalid for nuclear reactions) Properties of Matter Observable, measureable characteristics Use to describe, classify, and identify Expressed as either qualitative or quantitative Physical States of Matter Types of Solids Crystalline Solid ◦ Atoms or molecules are arranged in repeating patterns Amorphous Solid ◦ Atoms or molecules do not have any long range order Qualitative vs. Quantitative ◦ Qualitative Estimated No measuring device needed ◦ Quantitative Value + appropriate units Need to use measuring device/ instrument Quantitative Properties Reliable measurements need… ◦ Proper selection, use of measurement device ◦ Appropriate set of units (metrics/ SI units) Scientific Notation ◦ Ability to compactly express large and small numbers Dimensional Analysis ◦ Convert units as necessary ◦ Factor- label, unit factor Intensive vs. Extensive properties Intensive Properties ◦ Do not depend on size, extent, amount ◦ Only depend on identity, purity and conditions of measurement (temperature, pressure) ◦ Not additive Extensive Properties ◦ DO depend on the amount ◦ Are additive ◦ Different materials can have same value Properties are EITHER intensive or extensive, not both Intensive vs. Extensive Intensive or Extensive? Color Odor Mass Weight Malleability Volume Melting or freezing point Density Hardness Length Conductivity Types of Matter Pure Substances ◦ Substance made of a single type of atom or molecule ◦ Broken into elements and compounds Elements- substance that cannot be broken into simpler substances Compound- substance composed of two or more substances Types of Matter Mixtures ◦ Combination of two or more pure substances Homogeneous Two or more substances mixed with same composition Solution Does not settle out over time Heterogeneous Two or more pure substances with varied composition Does settle out over time Colloids and suspensions Classification of Matter Classification of Matter Practice Element, Compound, Heterogeneous Mixture or Homogeneous Mixture Jello Mint chocolate chip ice cream Chicken noodle soup Helium Water Diamond Tea Iced tea Sour cream Peanut butter Sodium chloride Carbon dioxide Oxygen Physical and Chemical Changes Physical Change Chemical Change Physical Property Chemical property Alters only state or appearance Atoms rearrange into different substance Extensive Property Intensive Property Changes back easily Needs chemical reaction to change back Still considered same thing afterwards No longer considered original substance Physical or Chemical Change? Butter melting Wood rotting Melting gold Grating cheese Turning sugar to caramel Nail rusting Digesting food Lighting a stove Tearing paper
