Question

Carbon dioxide
Hydrogen gas
Magnesium
Sodium chloride
Methane
Potassium
Which of the substances are compounds

Answer 1

In the list you provided, the substances that are compounds are:

1. **Carbon dioxide (CO₂)** - a compound composed of carbon and oxygen.
2. **Sodium chloride (NaCl)** - a compound composed of sodium and chlorine.
3. **Methane (CH₄)** - a compound composed of carbon and hydrogen.

The other substances listed are not compounds:

- **Hydrogen gas (H₂)**: an elemental gas, not a compound.
- **Magnesium (Mg)**: a metallic element, not a compound.
- **Potassium (K)**: an elemental metal, not a compound.

So, the compounds in your list are carbon dioxide, sodium chloride, and methane.