Answer: molecules.
- A atoms
- B electrons
- C protons
- D molecules
Correct answer: D. molecules
Explanation: Avogadro's law: under identical conditions of temperature and pressure, equal volumes of all gases contain an equal number of molecules.
Mass connects to moles via molar mass, and moles connect to particle count via Avogadro's number or to gas volume via the 22.4 L/mol rule at STP.
Concept context
The mole is chemistry's counting unit. Learn to relate mass, volume, and number of particles using Avogadro's number and molar mass, the foundation of all stoichiometry and reaction calculations.