Alkane Quiz
Questions: 16 · 10 minutes
1. Which condensed formula represents 2,2-dimethylpropane?
C(CH₃)₄ — a central carbon bonded to four methyl groups
CH₃CH(CH₃)CH₂CH₃ — the structure of 2-methylbutane
CH₃CH₂CH₂CH₂CH₃ — the straight-chain structure of pentane
CH₃CH(CH₃)CH₃ — the structure of 2-methylpropane
2. When naming a branched alkane, which chain is normally selected as the parent chain?
The chain with the greatest number of visible branches
The chain written horizontally in the displayed structure
The chain beginning nearest the left side of the displayed structure
The longest continuous carbon chain
3. Which name matches the condensed structure CH₃CH(CH₃)CH₃?
Butane
2-methylbutane
1-methylpropane
2-methylpropane
4. During a cracking problem, a student must choose an atom-balanced equation for C₁₀H₂₂ splitting into one smaller alkane and one alkene. Which equation works?
C₁₀H₂₂ → C₆H₁₄ + C₄H₁₀ — hexane plus butane
C₁₀H₂₂ → C₇H₁₆ + C₃H₈ — heptane plus propane
C₁₀H₂₂ → C₆H₁₄ + C₄H₈ — hexane plus butene
C₁₀H₂₂ → C₈H₁₈ + C₂H₆ — octane plus ethane
5. Hexane and 2,2-dimethylbutane have the same molecular formula. Which is expected to have the higher normal boiling point?
2,2-dimethylbutane, because branching always strengthens intermolecular forces
Hexane, because its less-branched shape allows more surface contact between molecules
It cannot be compared unless their combustion energies are known
They must have identical boiling points because they share a molecular formula
6. A hexane parent chain has a methyl group on carbon 2 and an ethyl group on carbon 3. How should the complete name be written?
2-methyl-3-ethylhexane
4-ethyl-5-methylhexane
3-methyl-2-ethylhexane
3-ethyl-2-methylhexane
7. Which condensed structure represents 2,3-dimethylbutane?
CH₃CH(CH₃)CH(CH₃)CH₃ — methyl branches on carbons 2 and 3
CH₃C(CH₃)₂CH₂CH₃ — two methyl branches on carbon 2
CH₃CH₂CH(CH₃)CH₂CH₃ — one methyl branch on carbon 3
CH₃CH₂CH₂CH₂CH₂CH₃ — an unbranched six-carbon chain
8. In 2-methylpropane, the central carbon is bonded directly to three other carbon atoms. How is that carbon classified?
Primary
Secondary
Tertiary
Quaternary
9. What is the molecular formula of hexane?
C₆H₁₀ — ten hydrogen atoms
C₆H₁₂ — twelve hydrogen atoms
C₆H₁₄ — fourteen hydrogen atoms
C₅H₁₂ — five carbon atoms and twelve hydrogen atoms
10. Analyze CH₃CH(CH₃)CH(CH₂CH₃)CH₂CH₃. What is its systematic name?
3-isopropylpentane
3-ethyl-4-methylpentane
3-ethyl-2-methylpentane
2-methyl-3-ethylpentane
11. How many structural isomers does pentane have?
Two
Three
Four
Five
12. What is the systematic name of CH₃CH₂CH₂CH₃?
Propane
Butane
Pentane
2-methylpropane
13. Apply the lowest-locant rule to CH₃CH₂CH₂CH₂CH(CH₃)CH₃. What is its correct name?
5-methylhexane
2-ethylpentane
Heptane
2-methylhexane
14. A five-carbon parent chain has one methyl group attached to its middle carbon. What is the compound's name?
3-methylpentane
2-ethylbutane
2-methylpentane
3-methylhexane
15. Which equation shows the complete combustion of propane with the smallest whole-number coefficients?
C₃H₈ + 3O₂ → 3CO₂ + 4H₂O
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
2C₃H₈ + 5O₂ → 6CO₂ + 8H₂O
C₃H₈ + 4O₂ → 3CO + 4H₂O
16. What is the general molecular formula for an acyclic alkane containing n carbon atoms?
CₙH₂ₙ₊₂ — the saturated acyclic formula
CₙH₂ₙ — the formula associated with one ring or double bond
CₙH₂ₙ₋₂ — the formula associated with two degrees of unsaturation
CₙHₙ₊₂ — a hydrogen count that is too low for an alkane