Josiah and Alicia have been excited all week because their science teacher has arranged for a guest speaker to present a lesson to their class on Friday. The guest speaker is a chemist. She spends part of the time explaining methane to the class. The chemist tells them methane is a flammable gas that can be formed when organic waste decomposes in a landfill. Methane is also present in natural gas, which is a fossil fuel. When methane reacts with oxygen gas, compounds called carbon dioxide and water are formed.

Question

How would you expect the boiling point of methane to compare with the boiling point of water?

The boiling points would probably be the same, because products and reactants always have the same properties.

The boiling points would probably be different, because products and reactants usually have different properties.

It is impossible to tell, because chemical reactions don't give us any clues about the properties of products compared to reactants.

Answer 1

The correct reasoning would be:

The boiling points would probably be different, because products and reactants usually have different properties.

Methane (CH₄) and water (H₂O) are different substances with distinct molecular structures and forces acting between their molecules. Methane is a simple hydrocarbon and has a boiling point of about -161.5°C. In contrast, water has a higher boiling point of 100°C due to hydrogen bonding, which is a strong intermolecular force. Therefore, it is expected that their boiling points would differ significantly.