which of the following variable controls the physical properties of a perfect gas?
a. pressure
b. temperature
c. volume
d. all of the above
e. atomic mass
The correct answer is d. all of the above.
To understand why all of the above variables control the physical properties of a perfect gas, it is important to have a basic understanding of what a perfect gas is. A perfect gas is an idealization that assumes molecules or atoms do not interact with each other and occupy no volume. While no real gas precisely fulfills these assumptions, the concept of a perfect gas is often used to simplify calculations in thermodynamics and other fields of science.
Let's go through each variable to understand their impact on the physical properties of a perfect gas:
1. Pressure (Answer: a): Pressure is the force exerted by gas molecules on the walls of their container per unit area. It is determined by the frequency and force of the molecular collisions with the container walls. In a perfect gas, the pressure is directly proportional to the number of gas molecules and the average kinetic energy of the molecules.
2. Temperature (Answer: b): Temperature is a measure of the average kinetic energy of the gas molecules. It determines the speed at which gas molecules move and collide with each other as well as the average energy of their collisions. In a perfect gas, the temperature is directly proportional to the average kinetic energy of the molecules and thus affects other properties such as pressure and volume.
3. Volume (Answer: c): Volume is the amount of space occupied by a gas. It can be influenced by factors such as the number of gas molecules and the temperature. In a perfect gas, the volume is directly proportional to the number of gas molecules and inversely proportional to the pressure.
4. Atomic mass (Answer: e): While atomic mass does not directly control the physical properties of a perfect gas, it does affect the behavior of real gases. The average speed of gas molecules is inversely proportional to the square root of their atomic or molecular mass. This is known as the root-mean-square speed. Therefore, gas molecules with higher atomic mass will have lower average speeds, affecting properties such as pressure and temperature.
In summary, all of the listed variables (pressure, temperature, volume, and atomic mass) have an impact on the physical properties of a perfect gas, making the correct answer d. all of the above.