Question

The Maxwell-Boltzmann distribution law of molecular speeds of graphically represented as:
This curve has which of the following characteristics?

• A. It has symmetrical distribution.
• B. The point A on x-axis represents the most probable speed.
• C. The area under the curve gives the total number of molecules.
• D. The maximum shifts to the right as the temperature increases.

Answer 1

Answer: (C), (D)

The correct options are
C The area under the curve gives the total number of molecules.
D The maximum shifts to the right as the temperature increases.

In this graph there are three lines. These are drawn for the same number of particles but for different temperatures. For now concentrate on the one marked 273K (0C). You should notice that there are few particles with low speeds, many with medium speeds and few with high speeds. The area below the line represents the total number of particles in the gas.
look at the 373K (100C) line, total number of particles is the same so the total area under the line is the same, but more particles have the faster speeds. The line has to get lower because the area underneath it can't change.
Notice that at the very highest speeds, the area under the line is very dependent on the temperature. For most reactions, number of these molecules increases very rapidly as the temperature is raised. Therefore, even small increases in temperature can cause a large increase in the number of particles