Humber Admissions Practice Test

Which law states that the volume of gas is directly proportional to the number of moles when temperature and pressure are held constant?

1. Boyle's Law

2. Charles' Law

3. Avogadro's Law

4. Gay-Lussac's Law

The correct answer is: Avogadro's Law

The correct answer is Avogadro's Law, which states that the volume of a gas is directly proportional to the number of moles of the gas when temperature and pressure are held constant. This relationship can be summarized with the equation V ∝ n, where V represents volume and n represents the number of moles. Essentially, if you increase the number of moles of gas while keeping the temperature and pressure constant, the volume will also increase proportionally. This principle is particularly relevant in chemical reactions and practical applications involving gas behavior. Understanding Avogadro's Law is crucial in the study of gas behavior and stoichiometry in chemistry, as it allows for the prediction of how gas volumes change with the number of moles. This is a fundamental concept in the ideal gas law, which integrates Avogadro's ideas with those of other gas laws. The other options represent different gas laws: Boyle's Law relates pressure and volume at constant temperature, Charles' Law connects volume and temperature at constant pressure, and Gay-Lussac's Law pertains to pressure and temperature at constant volume. Each law describes unique relationships between specific gas properties, emphasizing the importance of understanding Avogadro's contributions in the context of gas behavior.