Identify each item as either an element or a compound.

A. carbon (C)
B. carbon dioxide [tex]CO_2[/tex]
C. hydrogen (H)
D. sodium chloride [tex]NaCl[/tex]



Answer :

To identify each item as either an element or a compound, let's carefully consider their chemical structure and composition:

1. Carbon (C):
- Carbon is a pure substance consisting of only one type of atom, specifically carbon atoms.
- Substances consisting of only one type of atom are classified as elements.
- Therefore, carbon (C) is an element.

2. Carbon Dioxide (CO₂):
- Carbon dioxide is a chemical substance composed of carbon and oxygen atoms.
- Specifically, it consists of one carbon atom bonded to two oxygen atoms (hence, CO₂).
- Substances composed of two or more different types of atoms chemically bonded together are classified as compounds.
- Therefore, carbon dioxide (CO₂) is a compound.

3. Hydrogen (H):
- Hydrogen is a pure substance consisting of only one type of atom, specifically hydrogen atoms.
- Substances consisting of only one type of atom are classified as elements.
- Therefore, hydrogen (H) is an element.

4. Sodium Chloride (NaCl):
- Sodium chloride is a chemical substance composed of sodium and chlorine atoms.
- Specifically, it consists of one sodium atom chemically bonded to one chlorine atom (hence, NaCl).
- Substances composed of two or more different types of atoms chemically bonded together are classified as compounds.
- Therefore, sodium chloride (NaCl) is a compound.

In summary, the items are classified as follows:
- Carbon (C): Element
- Carbon Dioxide (CO₂): Compound
- Hydrogen (H): Element
- Sodium Chloride (NaCl): Compound