PPT-Chapter 10 The Mole Atomic Mass

Atomic mass Atoms of different elements have different masses Mass of a single atom is incredibly small so a special unit called atomic mass unit amu is used Atomic Mass Atoms are composed of three particles. S-C-8-1_The Mole Presentation. Source: http://en.wikipedia.org/wiki/Mole_(animal). The Mole. The mole is a counting unit for chemists, the same way a baker uses a dozen.. 1 dozen = 12 objects. 1 mole = . Calculate the following percentage by mass:. percent = portion/total x 100. If two samples are the same substance, they should have the . same percent composition by mass.. A compound will have the same physical and chemical characteristics.. Q: how long would it take to spend a mole of $1 coins if they were being spent at a rate of 1 billion per second?. Background: atomic masses. Look at the “atomic masses” on the periodic table. What do these represent?. The lab technician shown here is using a magnifying lens to examine a bacterial culture in a petri dish. When scientists cannot see the details of what they study, they try to obtain experimental data that help fill in the picture.. I. Foundations of the Atomic Theory. A. 400 B.C. –Democritus. 1. Defined nature’s basic particles as . atoms. a. means indivisible. B. 350 B.C. Aristotle. 1. said matter was made of the 4 “elements”. Pre-AP Chemistry. Charles Page High School. Stephen L. Cotton . Section 4.1 Defining the Atom. The Greek philosopher . Democritus. He believed that atoms were . indivisible. . and . indestructible. Dalton’s Atomic Theory. BASIC CHEMISTRY. CHM 138. Dalton’s Atomic Theory (1808). 1.. . Elements are composed of extremely small particles called . atoms. . . 2. All . atoms. of a given element are . identical, having the same size, mass and chemical properties. Composition of Substances and Solutions Atomic Mass and Formula Mass; Mole & Molar Mass; Percent Composition of Compounds; Determination of Empirical & Molecular Formulas; Molarity Other Units for Solution Concentrations Chemical Quantities. Measuring doughnuts:. 1 dozen = 12 doughnuts (count) . 1 dozen = 500 g doughnuts (mass). 1 dozen = 1 box doughnuts (volume). Measuring steam (H. 2. O gas):. 1 mole = 6.02 x 10. 23 . 1 mole of a substance is 6.02 x 10. 23. . representative particles. .. Avogadro’s number = . 6.02 x 10. 23. Avogadro determined the difference between atoms and particles.. Representative particle. The Mole602 X 1023in scientific notationThis number is named in honor of Amedeo Avogadro 1776 18561 dozen cookies 12 cookies100 cookies 102 cookiesA million of cookies 106 cookies1 mole of cookies The Mole in Chemistry . Not this!!. Not this!!!. The Mole. The mole is a counting unit. 1 pair = 2. 1 dozen = 12. 1 mole = 6.022 x 10. 23. atoms. This number is known as Avogadro’s number after Italian chemist . Chapter 9. History. About 200 years ago scientists needed a unit of measure that connected the mass of a molecule or atom with how many of them there were. . Amadeo Avogadro proposed his hypothesis in 1811. At that time, there was no data on the number of particles in a mole, or an agreement on any atomic weights or the standard. . 23. How do you measure how much?. You can measure mass, . or volume,. or you can count pieces.. We measure mass in grams.. We measure volume in liters.. We count pieces in . MOLES.. . Counting. . Counting words are used to simplify a description of a number of items. .