Exam 2 Study Guide

Exam 2 Study Guide - 2.9 Molar Mass: Counting Atoms by...

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2.9 Molar Mass: Counting Atoms by Weighing Them Converting Between Number of Moles and Number of Atoms moles (mol X)→number of atoms (X atoms): mol X (6.022 * 10 23 X atoms / 1 mol X) = X atoms Converting Between Mass and Amount (Number of Moles) mass (g X)→moles (mol X): g X ( 1 mol X / g X ) = mol X mass (g X)→moles (mol X)→number of atoms (X atoms): g X (1 mol X / g X) (6.022 * 10 23 X atoms / 1 mol X) = X atoms 3.1 Hydrogen, Oxygen, and Water The properties of compounds are different from the elements they are made up of. Water has a completely different set physical and chemical property from hydrogen or oxygen, the elements it is composed up of. Name Hydrogen Oxygen Water Molecular formula H2 O2 H2O BP/MP, °C -253/-259 183/-218 100/0 Physical state gas gas liquid Combustibility yes yes no 3.2 Chemical Bonds Ionic bond – Form between metal and nonmetal Electron transfers from metal to nonmetal Oppositely charged ions form Covalent bond – Between two nonmetals, sharing electrons between the two Shared electrons bring the two nuclei closer 3.3 Representing Compounds: Chemical Formulas and Molecular Models 3.4 An Atomic-Level View of Elements and Compounds Atomic Element ~ exist in nature as single atoms: Na(s) Cr(s) Al(s) Molecular Element ~ exists in nature as molecules: H 2 (g) O 2 (g) F 2 (g), Cl 2 (g), Br 2 (l), I 2 (s), P 4 (s), Se 8 (s) S 8 (s) Ionic Compound ~ Compound between a metal and a nonmetal Molecular Compound ~ 2 or more nonmetals 3.5 Ionic Compounds: Formulas and Names
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This note was uploaded on 02/15/2011 for the course CHEM 141 taught by Professor Milner,e during the Fall '08 term at Jackson State.

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Exam 2 Study Guide - 2.9 Molar Mass: Counting Atoms by...

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