Which statement about the Ideal Gas Constant R is true?

Which statement about the Ideal Gas Constant R is true?

• A. It is the same for all ideal gases.
• B. It depends on the particular gas.
• C. It varies with temperature.
• D. It only applies to diatomic gases.

Answer: (A)

R is the universal proportionality constant that appears in the ideal gas law PV = nRT. The reason it’s the same for all ideal gases is that, in the idealized model, the microscopic details of the molecules don’t affect the macroscopic relationships between pressure, volume, and temperature. One mole of any ideal gas obeys the same relationship between P, V, and T, so the constant that links these quantities must be universal. Its value reflects fundamental constants and is the same whether the gas is monatomic, diatomic, or polyatomic (as long as the gas behaves ideally). R does not vary with temperature in the ideal gas framework, though real gases show deviations at certain conditions.

R is the universal proportionality constant that appears in the ideal gas law PV = nRT. The reason it’s the same for all ideal gases is that, in the idealized model, the microscopic details of the molecules don’t affect the macroscopic relationships between pressure, volume, and temperature. One mole of any ideal gas obeys the same relationship between P, V, and T, so the constant that links these quantities must be universal. Its value reflects fundamental constants and is the same whether the gas is monatomic, diatomic, or polyatomic (as long as the gas behaves ideally). R does not vary with temperature in the ideal gas framework, though real gases show deviations at certain conditions.