Lattice Enthalpy
Periodic Trends:
Higher charge → larger lattice energy (Al2O3 > MgCl2 > NaCl)
Smaller ions → larger lattice energy
See Table 12.3.1 for examples (NaF, NaCl, MgCl2, Al2O3)
16 Matching Annotations
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Lattice Energy
Coulomb's Law Lattice Energy Equation
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Supercritical Fluids
Above critical T & P: gas & liquid indistinguishable.
High T > KE dominates (gas-like), high P > density rises (liquid-like).
Critical point = phase boundary disappears; forms supercritical fluid.
Practical: carbon capture, deep-sea volcanic fluids.
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Boiling Point and Hydrogen Bonds
Consider IMF + molecular mass + H-bonds.
Ex: H2O BP > HF due to more hydrogen bonds despite lighter mass.
Group 4 hydrides: BP increases down the group due to mass + polarizability.
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Small ΔHvap,AΔHvap,A\Delta H_{vap,A} and high T favor large Vapor Pressures because the fraction e−ΔHvap,ARTe−ΔHvap,ARTe^{-\frac{\Delta H_{vap,A}}{RT}} approaches 1. Large ΔHvap,AΔHvap,A\Delta H_{vap,A} and low T favor low Vapor Pressures because the fraction e−ΔHvap,ARTe−ΔHvap,ARTe^{-\frac{\Delta H_{vap,A}}{RT}} approaches 0.
Key Hvap rules
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enthalpy of vaporization
High ΔHvap > molecules prefer liquid > lower VP.
Always positive; used in Clausius-Clapeyron.
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Vaporization and Condensation
vaporization = energy IN, Condensation = energy OUT.
Vapor vs Gas: vapor implies coexistence w/ liquid or solid
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Introduction
Know definitions + connections between IMFs & liquid behavior.
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deshielded proton
When a highly electronegative atom (like N, O, or F) bonds with a hydrogen atom, it pulls electron density away from hydrogen, creating a partial positive charge on the hydrogen atom. This 'deshields' the hydrogen's proton, making it more attractive to lone pairs of electrons on other electronegative atoms, thus facilitating hydrogen bonding.
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Requirements for Hydrogen Bonding
Requirements for Hydro-Bonding
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Factors that Influence Polarizability
Polarizability Factors
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equation
dipole-dipole potential energy equation
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Equation
Ion Dipole Potential Equation
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Hydration Energy
Hydration Energy Trends for Cations
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αα\alpha means "proportional to" (the proportionality constant depends on the medium) rrr is the distance of separation. qqq is the charge of the ion ( only the magnitude of the charge is shown here.) kkk is the proportionality constant (Coulomb's constant). μμ\mu is the permanent dipole moment of the polar molecule (sections 8.7.4.2 and 8.8). From section 8.7 and 8.8 we treat define the dipole moment by the following equation
Basic variable explanation
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Molecular Geometries
Are we expected to memorize the Molecular Geometries relating to their bonds and lone pairs?
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