Unit 1: Sigfigs and Nomenclature AP Chem 2016-2017 Mrs. Han Matter A. Pure Substance: doesn?t change composition, fixed properties 1. Molecule: covalent bond 2. Compound: ionic bond B. Mixture: two or more pure substances 1. Properties change C. States of Matter 1. Solid: strong attraction, low kinetic Energy, constant volume and shape 2. Liquid: constant volume, shape changes 3. Gas: no set volume or shape Energy A. Definition: ability to do work, apply force to make molecules move 1. Kinetic: energy of motion 2. Potential: stored energy due to position 3. ET: total energy is the sum of kinetic and potential B. 1st Law of Thermodynamics 1. Conservation of energy, energy cannot be created or destroyed II. Significant Figures A. Accuracy vs. Precision