Sure! Let's identify whether each molecule is a compound or an element.
1. [tex]\( NaHCO_3 \)[/tex] (Sodium bicarbonate):
- This molecule contains four different elements: Sodium (Na), Hydrogen (H), Carbon (C), and Oxygen (O).
- Since it contains more than one type of element, it is a compound.
2. [tex]\( O_3 \)[/tex] (Ozone):
- This molecule contains only one type of element, Oxygen (O).
- Since it is composed of a single element, it is not considered a compound but an element.
3. [tex]\( Cl_2 \)[/tex] (Chlorine gas):
- This molecule contains only one type of element, Chlorine (Cl).
- Since it consists of a single element, it is not a compound but an element.
4. [tex]\( C_8H_{18} \)[/tex] (Octane):
- This molecule contains two different elements: Carbon (C) and Hydrogen (H).
- Since it contains more than one type of element, it is a compound.
Therefore, the two molecules that are compounds are:
[tex]\[ \boxed{NaHCO_3 \text{ and } C_8H_{18}} \][/tex]
