CHM 115 Final Exam Review

O–H stretch (IR)

3200–3600 cm⁻¹, broad.

N–H stretch (IR)

~3300 cm⁻¹, sharp.

C=O stretch (IR)

~1700 cm⁻¹, strong.

C=C stretch (IR)

1600–1680 cm⁻¹.

Alkane C–H stretch

~2900 cm⁻¹.

Ionization energy trend

Increases across, increases up.

Atomic radius trend

Decreases across, increases down.

Electron affinity trend

Becomes more negative across a period.

Electronegativity trend

Increases across, increases up.

Kelvin requirement

All gas laws require Kelvin.

Limiting reactant steps

Convert to moles → mole ratio → smallest product = limiting reactant.

Gas constant R

0.08206 L·atm/mol·K.

Molarity

M = moles / liters of solution.

Density gas law

d = PM/RT.

Electron vs molecular geometry

Electron = all electron groups; molecular = bonded atoms only.

Tetrahedral geometry

109.5°, sp³.

Trigonal planar geometry

120°, sp².

Bent (3 groups, 1 lone pair)

<120°, sp

Bent (4 groups, 2 lone pairs)

~104.5°, sp³.

Hybridization sp²

Trigonal planar regions.

Hybridization sp³

Tetrahedral regions.

Hybridization sp

Linear regions.

Intermolecular forces (3 types)

LDF, dipole-dipole, hydrogen bonding.

Hydrogen bond requirement

H bonded to N, O, or F.

IMF strength order

H-bond > dipole-dipole > LDF.

Isomer

Compounds with same formula, different structure.

Alcohol functional group

–OH.

Polymer

Long chain of repeating monomers.

Aromatic ring

Benzene-like conjugated ring.

Nitrate

NO₃⁻

Nitrite

NO₂⁻

Sulfate

SO₄²⁻

Sulfite

SO₃²⁻

Ammonium

NH₄⁺

Hydroxide

OH⁻

Carbonate

CO₃²⁻

Phosphate

PO₄³⁻