Define cation and anion.

What is the difference between an endergonic and an exergonic reaction?

Define an ion.

Explain why water expands when it freezes.

How does an enzyme facilitate a chemical reaction?

What do photosynthesis and cellular respiration have in common?  Which reaction is endergonic?

What kind (not the name) of molecule is this  ?

What do the following all have in common?  nucleic acids, lipids, carbohydrates, and proteins.

Explain two ways hydrocarbons can be harmful.

Describe the difference between a double replacement reaction and a single replacement reaction?