Properties of Small Molecules Flashcards
All 6 cards in this deck
What states are substances made of small molecules usually in at room temperature?
Gases or liquids, because they have relatively low melting and boiling points.
Which forces are overcome when a substance made of small molecules melts or boils?
The weak intermolecular forces between the molecules — not the covalent bonds inside them.
True or false? Simple molecular substances have low boiling points because their covalent bonds are weak.
False. The covalent bonds are strong; it is the intermolecular forces between molecules that are weak.
Why do substances made of small molecules not conduct electricity?
The molecules do not have an overall electric charge, so there is nothing to carry charge.
How do the intermolecular forces of molecular substances change as the molecules get larger?
They increase in strength, so larger molecules have higher melting and boiling points.
What are the steps to explain why one molecular substance has a higher boiling point than another?
e.g. butane boils at a higher temperature than methane
State the size difference: butane has larger molecules.
Larger molecules have stronger intermolecular forces.
More energy is needed to overcome them, so the boiling point is higher.