Which one of the following statements regarding ideal gas laws is FALSE?
Select one:
a. An ideal gas has an infinite heat capacity
b. The macroscopic ideal gas equation is PV = nRT
c. The temperature must always be measured in Kelvin (K)
d. A single molecule of gas has kinetic energy E = 3/2 kT
which do you think and why?
To determine which statement regarding ideal gas laws is false, we need to evaluate each statement individually:
a. An ideal gas has an infinite heat capacity: We can check the definition of an ideal gas to see if it supports this statement. An ideal gas is a theoretical concept where the gas molecules do not interact with each other, have no volume, and have no intermolecular forces. However, even though an ideal gas does not experience phase changes or undergo chemical reactions, it still has a finite heat capacity. Therefore, this statement is FALSE.
b. The macroscopic ideal gas equation is PV = nRT: The ideal gas equation, also known as the macroscopic ideal gas equation, is stated as PV = nRT, where P represents pressure, V represents volume, n represents the number of moles of gas, R is the ideal gas constant, and T represents temperature. This equation is a fundamental equation in chemistry and it accurately describes the behavior of an ideal gas. Therefore, this statement is TRUE.
c. The temperature must always be measured in Kelvin (K): In the ideal gas laws, temperature must be measured in Kelvin (K) rather than Celsius (°C) or Fahrenheit (°F). This is because the Kelvin scale is an absolute temperature scale where 0 K represents absolute zero (the point at which all molecular motion stops), while Celsius and Fahrenheit scales have arbitrary zero points. Therefore, this statement is TRUE.
d. A single molecule of gas has kinetic energy E = 3/2 kT: According to the kinetic theory of gases, which is the foundation of the ideal gas laws, the average kinetic energy (KE) of a gas molecule is directly proportional to the temperature (T) of the gas. The relationship is often written as KE = (3/2)kT, where k is Boltzmann's constant. However, the statement in question refers to a single molecule of gas, and it can have any amount of kinetic energy depending on its instantaneous velocity and mass. Therefore, this statement is TRUE.
In conclusion, the false statement regarding ideal gas laws is statement (a): An ideal gas has an infinite heat capacity.