CHEM 120 Lecture 1: CHEM 120 Lecture 1
Document Summary
Significant figures are a way to quantify uncertainty in a measurement. Two kinds of tasks related to significant figures: counting the number of significant figures in a given number, conducting mathematical operations using measurements with different uncertainties. Multiply by the unit factor to do the conversion: 2. 2 quarts = 2. 2 quarts x (1 liter)/(1. 0567 quarts) = 2. 08195 liters. Wood, air, soil, wine, brass: homogenous mixture: also called a solution, it has visibly indistinguishable parts, ex. Mixture of sugar and water: heterogenous mixture, it has visibly distinguishable parts, ex. Pure substances: pure substances have constant composition. Pure water, a block of pure copper metal: pure substances are made up of elements or compounds, compounds are made of elements. Separation of mixtures into pure compounds: a mixture can be separated into compounds by undergoing a physical change, a physical change is the change in form of a substance, not its chemical composition.
