Purpose: Check SCH3U prerequisites (bonding, hydrocarbon basics, balancing) before organic chemistry.
Q1 — Bonding (SCH3U)
Draw the Lewis structure of methane (CH₄). How many bonding pairs and lone pairs around C?
Reveal expected answer
C central, 4 single bonds to H. 4 bond pairs, 0 lone pairs.
Q2 — Hydrocarbon formulas
General formulas for alkane / alkene / alkyne?
Reveal expected answer
CnH2n+2 / CnH2n / CnH2n−2.
Q3 — Naming
Name CH₃CH₂CH₂CH₃.
Reveal expected answer
Butane.
Q4 — Balancing
Balance: \( \text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \).
Reveal expected answer
2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O.
Q5 — Polarity
Is the C–O bond polar? Explain.
Reveal expected answer
Polar; ΔEN ≈ 0.9 (O 3.4, C 2.6).
Q6 — Self-confidence
Rate your comfort drawing structural formulas (1–4). What needs review?
Q7 — Predict
Pentane and 2-methylbutane share C₅H₁₂. Why might their boiling points differ?
Reveal expected answer
Branching reduces surface area / London forces; 2-methylbutane (28 °C) boils lower than n-pentane (36 °C).
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