Chapter 1
How many C's and H's are in CH₃CH₂CH₂CH₃?
4 carbons, 10 hydrogens (C₄H₁₀) - butane.
What is the conjugate base of acetic acid (CH₃CO₂H)?
Acetate ion (CH₃CO₂⁻)
Name this alkyl group: —CH₂CH₃
Ethyl
What is the hybridization for the middle Carbon in CH₃CH=CH2?
sp2
Which is more stable: CH₃⁺ or (CH₃)₃C⁺? Explain why.
(CH₃)₃C⁺ (tert-butyl) is more stable because alkyl groups donate electron density via the inductive effect and hyperconjugation, stabilizing the positive charge.
Label each carbon in CH₃CH₂CH₂CHO as 1°, 2°, 3°, or 4°.
C1: 1°, C2: 2°, C3: 3°, C4: 4°.
Draw all resonance forms for the nitrate anion
3 forms
O
||
O⁻—N⁺—O⁻
O⁻
|
O=N⁺—O⁻
O⁻
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O⁻—N⁺=O
Draw all resonance forms for the 2,4-pentanedione anion (I will draw) and identify the most stable one.
3 resonance forms. Most stable: the form with negative charge on oxygen (more electronegative than carbon).
Name this alkane: CH₃CH₂CH(CH₃)CH(CH₃)CH₂CH₃.
3,4-Dimethylhexane.
Number from either end gives substituents at C3 and C4 (same), so either direction is correct.
Give the molecular formula for CH₃CH₂CH=C=O
C4H6O
Acid HA has a pKₐ of 5.0, and acid HB has a pKₐ of 2.0. Write the dissociation equilibrium for each acid in water. Which equilibrium lies further to the right?
HA + H₂O ⇌ H₃O⁺ + A⁻ HB + H₂O ⇌ H₃O⁺ + B⁻
The HB equilibrium lies further to the right because HB has a lower pKa (2.0), meaning it is the stronger acid (acids prefer to doante H+).
Lower pKa = stronger acid = more dissociation.
Draw all three constitutional isomers of C₅H₁₂ and name each
Pentane CH₃CH₂CH₂CH₂CH₃
2-Methylbutane CH₃CH(CH₃)CH₂CH₃
2,2-Dimethylpropane C(CH₃)₄