CHEM 1211 Lecture 12 Outline of Last Lecture I Problem One II Problem Two III Dilution of Solution A Problem One IV Chemical Thermodynamics A Heat Transfer 1 Through a Liquid Outline of Current Lecture I Acid Concentrations 1 Example One 2 Example Two 3 Example Three CQ 1 4 Example Four 5 Example Five II Chemical Thermodynamics A Heat Transfer 1 CQ 2 2 CQ 3 3 Example One B Internal Energy NEW THERMODYNAMIC FXN 1 Example One Current Lecture I Acid Concentrations 1 Consider a 0 15M solution of hydrochloric acid What is the pH HCl aq H2O l H3O aq Cl aq pH log H or H3O log0 15 pH 0 823 x 1 pH 0 823 pH II 0 82 pH Acidic 2 Consider a 0 15M solution of sulfuric acid What is the pH pH log H3O log0 3 0 52 x 1 0 52pH Acidic 3 What is the pH of the sulfurous acid solution in the previous problem 1 84 x 10 3M pH 2 735 or 2 73 4 What is the H3O in a solution that has a pH of 8 677 H3O 10 pH H3O 10 8 677 2 10 x 10 9M BASIC 5 What is the H3O in a solution that has a pH of 2 144 H3O 10 2 144 7 18 x 10 3M Chemical Thermodynamics q heat J or KJ A Heat Transfer qSystem qSurroundings 0 m mass qSurroundings qSystem C specific heat q m x C x T T change in temp As T1 As T2 T2 melting freezing point q m x Cs x T As T2 Al T2 Melting q m x Hfusion Temperature doesn t change Al T2 Al T3 T3 boiling point q m x Cliquid x T Al T3 Ag T3 q m x Hvaporization endothermic 1 CQ 2 Which has the highest specific heat T E M P Heat Added 2 CQ 3 T E M P What is not physically possible exothermic Heat Added 3 2 56 mL of ethylene glycol is at 25 00 C How much heat must be transferred to change it into a gas at 212 0 C B Internal Energy NEW THERMODYNAMIC FXN U qp W p U qp P V qp U P V 1 2C8H18 l 25O2 g 16CO2 g 18H2O l H 136 6 KJ mol rxn What is the enthalpy change if you burn 1 00L of isooctane D 0 690g mL 1 00L 103mL 0 690g mol C8H18 1 mol rxn 136 6KJ L mL 114g C8H18 2 mol C8H18 mol rxn 4 13 x 102 KJ exothermic System RXN
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