2 After reading Section 11.3, you should know: The difference between fusion, solidification, vaporization and condensationHow to calculate the heat changes for each type of reaction
3 DefinitionsMolar heat of fusion (∆Hfus) – the heat absorbed by one mole of a substance in melting from a solid to a liquid at constant temperature.Table 11.5 (pg 308)Molar heat of solidification (∆Hsolid) – the heat released when one mole of a liquid solidifies at constant temperature.Determined from Table 11.5 (pg 308)
4 DefinitionsMolar heat of vaporization (∆Hvap) – the amount of heat absorbed when one mole of a given liquid is vaporized.Table 11.5 (pg 308)Molar heat of condensation (∆Hcond) – the amount of heat released when one mole of a vapor condenses.Determined from Table 11.5 (pg 308)
5 DefinitionsMolar heat of solution (∆Hsoln) – the heat change caused by the dissolution of one mole of a substance; can be absorbed or released.Molar heat of combustion (ΔHcomb) – heat of reaction for the complete burning of one mole of a substance.Table 11.4 (pg 305)
6 How they all relate (values on pg 308) Hsolid and Hfus are oppositesHsolid = - HvapH2O(s) --> H2O(l) Hfus = 6.01 kJ / molH2O(l) --> H2O(s) Hsolid = kJ / molHvap and Hcond are opposites, too!Hvap = - HcondH2O(l) --> H2O(g) Hvap = 40.7 kJ / molH2O(g) --> H2O(l) Hcond = kJ / mol
9 Sample ProblemHow many grams of ice at 0oC and kPa could be melted by the addition of 2.25 kJ of heat?Known Values: Unknowns:Melting = ∆Hfusion grams of ice = ?∆Hfusion (H2O) = 6.01 kJ/mol2.25 kJ of heat are absorbed? Grams = 2.25 kJ 1 mol grams = grams6.01 kJ mol
10 After reading Section 11.3, you should know: The difference between fusion, solidification, vaporization and condensationHow to calculate the heat changes for each type of reaction
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