Chem 1211 1st Edition Lecture 10 Outline of Last Lecture I II Acids and Bases Conjugate Acid Base Pairs Outline of Current Lecture I II Oxidation Reduction Reactions Stoichiometry Current Lecture I Oxidation Reduction Reactions a Oxidation loss of eb Reduction gain of ec Oxidation number for individual atoms i Atoms molecular elements in standard form oxidation number 0 ii Ions oxidation number charge iii Common values 1 H 1 2 F 1 3 O 2 iv ConcepTest Which oxidation numbers are correct for the indicated atom 1 Oxygen in O2 ON 0 2 Oxygen in HO ON 1 3 Oxygen in CO2 ON 2 a ANSWER 1 and 3 are correct When by itself an atom molecule has a charge of 0 otherwise oxygen has a charge of 2 v Reactions with oxygen are oxidation reactions 1 ConcepTest Which elements get oxidized and reduced respectively in the equation 2Fe2O3 s 3 C s 4Fe s 3CO2 g a Iron oxygen b Carbon iron c Carbon oxygen These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute d Iron carbon i ANSWER B Oxygen is 2 so iron in the 2Fe2O3 must have an oxidation number of 3 On the other side 4 Fe has an oxidation number of 0 Since it goes from 3 to 0 it is reduced Carbon is oxidized 2 ConcepTest For which reaction is an oxygen atom reduced and a chlorine atom oxidized a 2NaOCl F2 2 NaF Cl2 O2 b Cl2 2 O2 2ClO2 c 2NaCl O2 2 NaOCl d H2O2 2 NaCl Cl2 2 NaOH e None of these i Answer B Cl goes from O to 4 so it is oxidized and O goes from 0 to 2 so it is reduced However C and D are also correct 3 ConcepTest Which chemical reaction best describes the reaction 2AgNO3 aq Cu s 2Ag s Cu NO3 2 aq a Acid base b Precipitation c Gas forming d Oxidation reduction i Answer D 1 Acid base must make H make HO or combine H and HO2 Precipitation A B C D3 No gas is formed 4 ConcepTest Which chemical reaction type best describes the reaction CaO s H2O I Ca OH 2 s a Acid base b Precipitation c Gas forming d Oxidation reduction i Answer A makes OH II Stoichiometry a ConcepTest For the reaction 4 NH3 5 O2 4 NO 6 H2O how many N H and O i ANSWER 4 N 12 H 10 O b ConcepTest For the reaction aN2 bO2 N2aO2b if 2 8 g of N2 yields 9 2 g of N2aO2b what are a and b respectively i ANSWER B You used 6 4 grams of O Nitrogen is 14 so 2 14 is 28 a tenth of a gram
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