Chapter 12.2, Problem 17SSC

Interpretation Introduction

Interpretation:

The effect of number of bonds in methane and octane on the dispersion forces in their sample must be explained. The sample which is a gas and a liquid at room temperature must also be explained.

Concept introduction:

Dispersion force depends on the surface area or size of the molecule.

Answer to Problem 17SSC

More the surface area stronger is the dispersion force.

Methane is a gas and octane is a liquid at room temperature.

Explanation of Solution

Methane is a small molecule with 4 single bonds with the central C atom. On the other hand, octane is bigger molecule in which there are many atoms and bonds. Surface area of octane is much higher as compared to methane. So intermolecular force is stronger in octane as compared to methane.

Thus methane is a gas but octane is a liquid at room temperature.

Conclusion

Methane is a gas but octane is a liquid.