Intermolecular Forces: Quiz

Intermolecular Forces: Quiz

7 questions

1. Question 1EasyWhich forces are present between CH₄ molecules?

   Adispersion forces onlyBdipole–dipole forcesChydrogen bondsDionic bonds
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   Answer: dispersion forces only

   Methane is non-polar and has no H on N, O or F, so only dispersion forces act.

2. Question 2EasyWhich molecule can form hydrogen bonds with itself?

   ACH₃OCH₃BCH₃OHCHClDCH₄
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   Answer: CH₃OH

   Methanol has an H bonded directly to O. In CH₃OCH₃ all H atoms are on carbon.

3. Question 3EasyWhich halogen has the highest boiling point?

   AF₂BCl₂CBr₂DI₂
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   Answer: I₂

   All are non-polar; I₂ has the most electrons and the strongest dispersion forces (184 °C).

4. Question 4MediumWhich has the highest boiling point: butane, propanone or propan-1-ol (all about 58–60 g/mol)?

   AbutaneBpropanoneCpropan-1-olDthey are all the same
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   Answer: propan-1-ol

   With similar dispersion forces, propan-1-ol wins because it can hydrogen-bond (97 °C, against 56 °C and about 0 °C).

5. Question 5HardCO₂ has polar C=O bonds. What are its intermolecular forces?

   Adispersion forces onlyBdipole–dipole forcesChydrogen bondsDdipole–dipole and hydrogen bonds
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   Answer: dispersion forces only

   CO₂ is linear, so the two bond dipoles cancel and the molecule is non-polar.

6. Question 6MediumWhich is most soluble in hexane?

   AKClBsugarCI₂Dethanoic acid
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   Answer: I₂

   Like dissolves like: non-polar iodine dissolves in non-polar hexane.

7. Question 7MediumHow much energy is needed to vaporize 2.00 mol of water at 100 °C (ΔH(vap) = 40.7 kJ/mol)?

   A20.4 kJB40.7 kJC81.4 kJD733 kJ
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   Answer: 81.4 kJ

   q = 2.00 mol × 40.7 kJ/mol = 81.4 kJ.