t2guide - CHM111 Fall 2009 Choi& Ren Guide for Test 2...

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Unformatted text preview: CHM111 Fall 2009 Choi & Ren Guide for Test 2 Chapter 3 Chemical Compounds Ionic and Molecular Compounds (covered in T1) 1 2 Monatomic and Polyatomic Ions a) Focus on monatomic cations / anions; b) For polyatomic anions, see Ren’s Rendition (8th lecture) – memorize those in red. 3 4 Formulas for & Naming Ionic Compounds Charge neutrality for correct formulae; name cation first, then anion; Roman numeral for variable charge on metal Naming and Writing Formulas for Molecular Compounds a) naming is decided by positions in periodic table: element on the left retains the name of the element; element on the right names like an anion (using ide suffix) b) Greek prefix for multiplicity (Table 3.9) 6 Acids and Bases a) need to know the definition of acid / base b) naming of binary acids; naming of oxy acids with “‐ic” suffix Chapter 4 Chemical Composition 1. Mole Quantities ; Avogadro’s number (what does it represent?) 2. Moles (mol), Masses, and Particles molar mass, “g/mol” mol = mass / (molar mass) ; mass = mol x (molar mass) ; molar mass = mass/ mol Graphically, the relationships are shown below. divide by molar mass grams of substance divide by 6.022 x 1023 x molar mass moles of substance x 6.022 x 1023 numbers of atoms / molecules Applications Scenario 1, given mass, determining moles: divide mass (in g) by molar mass (HW7: Q8, Q11b) Scenario 2, given moles, calculating mass: multiply moles by molar mass (HW7: Q9, Q11a) Scenario 3, given mass, calculating number of molecules: step 1, divide mass (in g) by molar mass to get moles; step 2, multiply moles by Avogadro’s number. (HW8: Q3b, Q3c) Scenario 4, given mass, calculating number of atoms of a specified element E: step 1, divide mass (in g) by molar mass to get moles; step 2, multiply moles by Avogadro’s number; step 3, multiply by the number of E in the formula unit (HW7: Q10, Q11c) CHM111 Fall 2009 Choi & Ren Scenario 5, calculating the mass of a single atom or molecule in grams: step 1, molar mass of the atom or molecule; step 2, divide molar mass by Avogadro’s number. (HW8: Q1a, Q2a; T2‐2008, Q8 & Q15) Scenario 6, given number of molecules, calculating the moles and mass: step 1, getting moles by dividing number of molecules by Avogadro’s number; step 2, multiply moles by molar mass to get mass in g. (HW8: Q1b, Q1c; Q2b, Q2c; Q3a; T2‐2008, Q9) 3. Determining Empirical and Molecular Formulas mass% calculations; from either given masses, or formula mass% empirical formula molecular formula (with molar mass info) 4. Chemical Composition of Solutions: molarity (M) M = mol / V; mol = M x V; V = mol/M (watch out for the unit of V, “L” versus “mL”) Law of dilution: (M x V)concentrate = (M x V)dilute Also covered Math Tool Boxes 1.2 & 1.3 – pay attention to relevant homework questions, and Q1, Q7 from T2‐2008. Chapter 5 Chemical Reaction and Equations See my “week08” post. ...
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This note was uploaded on 02/14/2011 for the course CHEM 111 taught by Professor Cao during the Fall '07 term at Purdue.

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