Methane, CH₄, is a gas at room temperature.

a. Explain why methane is a gas at room temperature.

b. Draw a diagram to show the shape of a molecule of methane. On your diagram show a value for the bond angle.

c. Perfumes often contain molecules that have simple molecular structures. Explain why.

d. When a negatively charged rod is held next to a stream of propanone, CH₃COCH₃, the stream of propanone is attracted to the rod. Draw the full structure of a molecule of propanone and use your diagram to explain why the stream of propanone is attracted to the rod.