CHEM 1465 1st Edition Lecture 1Chapter 1 – Introduction to Chemistry What is Chemistry? The Study of matter and energy, and the changes they undergo.Three perspectives 1.Macroscopic: how we observe the world or matter around us.• Physical - Change in form but not in chemical ID- Examples: color, density, odor, and boiling• Chemical - Change in the chemical ID (the ID of the atoms or molecules change)- Examples: flammability or corrosiveness oStates of Matter 1. Solid: fixed shape and volume2. Liquid: variable shape and fixed volume3. Gas: variable shape and volume2. Microscopic: All matter is composed of atoms and molecules- Elements are like the building blocks- Atoms are small particles that cannot be made any smaller- Molecules are groups of atoms held together3. Symbolic: what chemist use to represent atoms, molecules, and reactions.- Reactions: A + B → C- Formulas: H2O → water- Elemental symbols: H, O, N, etc. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Ball and stick drawingsThe Science of Chemistry (observations in Science) Precision vs Accuracy - Precision: how closely individual measurements agree with each other- Accuracy: how closely measurements agree with an “accepted’ valueError - Random errors: fundamental to measurements associated with the limitations of the instrument. Ex) beaker versus a graduated cylinder- Systematic errors: consistently high or low of the accepted value and has an “unknown” bias. Ex) measuring a beaker without being at eye levelModels: largely empirical description- Theory: explanation grounded in a fundamental principle or assumption about the behavior of a system- Law: theories that have been accepted for hundreds of years and are considered self-evident. Numbers and Measurements SI units: international system of units Property UnitMass Kilogram (kg)Time Seconds (s)Distance Meters (m)Electric current Ampere (A)Temperature Kelvin (K)# of particles Moles (mol)Light intensity Candela
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