Question

question 2
which best identifies what is termed a gas?
nonmetal elements in the periodic table
solutions of small nonmetals
one or more substances in the gas phase
a substance that is in the atmosphere

Explanation:

• Option A: Not all nonmetal elements are gases (e.g., carbon is a nonmetal solid), so this is incorrect.
• Option B: Solutions are homogeneous mixtures, and "solutions of small nonmetals" is not a definition of a gas.
• Option C: A gas is defined as one or more substances in the gas phase (having no fixed shape or volume, particles far apart and moving freely). This matches the scientific definition.
• Option D: Many substances in the atmosphere are gases, but not all gases are in the atmosphere (e.g., gas in a sealed container), so this is not a defining characteristic.

Answer:

C. One or more substances in the gas phase