Question

understanding matter: molecules and compounds
what is a molecule?
two - more atoms chemically bonded together. they can be the same type of atom.
what is a compound?
a type of molecule made of two or more different types of atoms bonded together.
example: water (h₂o) is a compound.
matching practice
look at the picture. is it a molecule (same atoms) or a compound (different atoms)? draw a line from the item to the correct category.
water (h₂o)
oxygen gas (o₂)
salt (nacl)
nitrogen gas (n₂)
carbon dioxide (co₂)
molecule
compound

Explanation:

A molecule is two - or more atoms chemically bonded, and they can be the same type of atom. A compound is a type of molecule with two or more different types of atoms bonded. Water ($H_2O$) has hydrogen and oxygen atoms, so it's a compound. Oxygen gas ($O_2$) has only oxygen atoms, so it's a molecule. Salt ($NaCl$) has sodium and chlorine atoms, so it's a compound. Nitrogen gas ($N_2$) has only nitrogen atoms, so it's a molecule. Carbon dioxide ($CO_2$) has carbon and oxygen atoms, so it's a compound.

Answer:

Water ($H_2O$) - Compound
Oxygen Gas ($O_2$) - Molecule
Salt ($NaCl$) - Compound
Nitrogen Gas ($N_2$) - Molecule
Carbon Dioxide ($CO_2$) - Compound