Which term identifies a reaction that breaks apart macromolecules?

When determining the shape of a molecule, it is important to draw a lewis dot structure first in order to see the total number a. electrons within the moleculeb. bonding and unshared pairs around central atomc. unshared pair within the molecule( i really need it )

If 90.0 grams of ethane reacted with excess chlorine,how many grams of dicarbon hexachloride would form

What happens to isotopes that are unstable?