Humber Admissions Practice Test

Avogadro's Law explains the relationship between which two variables?

1. Temperature and pressure

2. Volume and temperature

3. Moles and volume

4. Pressure and volume

The correct answer is: Moles and volume

Avogadro's Law states that, at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of the gas present. This means that if you have more moles (which is a measure of the amount of substance) of a gas, the volume it occupies will increase correspondingly, assuming the temperature and pressure remain unchanged. This relationship illustrates that equal volumes of gases, at the same temperature and pressure, contain an equal number of moles, regardless of their chemical identity. In this context, the other options focus on different pairs of variables that are explained by other gas laws. For example, the relationship between temperature and pressure can be described by Gay-Lussac's Law, while the relationship between volume and temperature is covered by Charles’s Law. The relationship between pressure and volume is captured by Boyle’s Law. Each of these laws addresses specific interactions among gas properties, highlighting why moles and volume under Avogadro's Law is particularly significant within the study of gases.