3/24/2015
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Today:
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◦ Electron orbitals,
configurations, & quantum #s
◦ Periodic Trends, Lattice
Energies & Born Haber Cycles
◦ Lewis Dot Structures, VSEPR
Theory, & Polarity
◦ Stoichiometry
◦ Titrations
◦ Combustion Analysis
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Challenge Problem Set 8 DUE
tonight at 11 pm
Exam 2 Study guide available
online
Electron Transfer Energetics:
P(g) + 1e- → P-1(g)
1st Electron Affinity = -72 kJ/mol
P-1(g) + 1e- → P-2(g)
2nd Electron Affinity = +150 kJ/mol
P-2
3rd Electron Affinity = +578 kJ/mol
(g)
+
1e-
→
P-3
(g)
P(g) + 3e- → P-3(g)
ΔE = ?
Electron Transfer Energetics:
Which reaction would release the most energy?
Which reaction would require the most energy?
Ca+2(g) + 1e- → Ca+1(g)
Ca+1(g) + 1e- → Ca(g)
Ca(g) + 1e- → Ca-1(g)
Ca(g) → Ca+2(g) + 2e-
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3/24/2015
Rank the ionic compounds below from smallest lattice energy to
largest.
BaBr2, GaN, FrI, Ca3P2, SrSe
Which compound above would have the LOWEST melting point?
Rank the compounds below from lowest melting point to
highest melting point.
NaF
F2
HF
HCl
Cl2
Rank the compounds below from lowest to highest water
solubility.
HOCH2CH2CH2CH3
FCH2CH2CH2CH3
Na+ - OCH2CH2CH2CH3
CH3CH2OCH2CH3
Select most reasonable structure for O2NCHCHOH
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3/24/2015
Lewis Dot Structures:
Draw the Lewis dot structure for the substances below:
• CH3N3
Predict the N-N-N bond angle
• POCl3
Predict the Cl-P-Cl bond angle
How would the H-N-H bond angle change in the reaction below?
NH3 + H+ → NH4+
Practice Problems:
Urea (CH4N2O), a common fertilizer, can be synthesized by the reaction of
ammonia (NH3) with carbon dioxide.
2 NH3(aq) + CO2(aq)
CH4N2O(aq) + H2O(l)
An industrial synthesis of urea begins with 35.8 kg of ammonia and 89 kg of
carbon dioxide. What is the maximum mass of urea could theoretically be
produced from this starting mixture?
Combustion Analysis:
Caffeine, a stimulant found in coffee, tea, and certain soft drinks,
contains C, H, O, and N. Combustion of 1.000 mg of caffeine
produces 1.813 mg CO2, 0.4639 mg H2O, and 0.2885 mg N2. Based
on this analysis, determine the empirical formula of caffeine.
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