This problem is providing the average speed at which an argon atom moves at 25 °C and asks for the average wavelength it exhibits. At the end, the answer turns out to be 23.15 pm.
In chemistry, when analyzing the wavelength of objects or substances, one can use the Broglie's wavelength formula in order to relate the average speed, mass and wavelength with:
[tex]\lambda = \frac{h}{mv}[/tex]
Where h stands for the Planck's constant, m for the mass and v for the average speed. Now, since an argon atom has a mass of 39.948 amu
and 1 amu = 1.6605 x10⁻²⁷ kg, one can plug in these numbers to obtain:
[tex]\lambda = \frac{6.626x10^{-34}kg*\frac{m^2}{s} }{39.948amu*\frac{1.6605x10^{-27}kg}{1amu}*431.5\frac{m}{s} }\\\\\lambda=2.315x10^{-11}m*\frac{1x10^{12}pm}{1m}\\ \\\lambda=23.15pm[/tex]
Learn more about Broglie's wavelength: https://brainly.com/question/8752907
