Which gas law is commonly summarized as PV = nRT?

• A. Boyle's Law
• B. Charles' Law
• C. Combined Gas Law
• D. Ideal Gas Law

Answer: (C)

The main idea is how pressure, volume, temperature, and the amount of gas relate to one another. PV = nRT is the Ideal Gas Law, which describes the behavior of an ideal gas by linking P, V, n, and T with the universal gas constant R. It shows that the product of pressure and volume scales with temperature and the amount of substance: for a given gas, increasing temperature or the amount of gas increases PV, while changes in pressure or volume adjust to maintain the relationship.

The universal gas constant R has units that depend on how you measure pressure and volume (for example 0.0821 L·atm/(mol·K) or 8.314 J/(mol·K)). This law is a comprehensive framework for predicting how gases behave when any of the variables change, as long as the gas behaves ideally.

The combined gas law relates P, V, and T for a fixed amount of gas and is often written in forms like P1V1/T1 = P2V2/T2. It describes how those three variables interconvert when n is constant, but it does not explicitly include the amount of substance, which is why PV = nRT is the more general expression for an ideal gas.