In the HCI molecule the separation between the nuclei of the two atoms is about `1.27xx10^(-10)` m. Find the approximate location of the Centre of mass of the molecule. Given that a chlorine atom is about 35.5 times as massive as a hydrogen atom and nearly all the mass of an atom is concentrated in its nucleus.

Explanation

Let the mass of the H-atom be m. So the mass of theCl-atom is 35.5 m. In the Fig r= `1.27xx10^(-10)`m
Let the coordinate of the H-atom, `x_(1)`=0, then the coordinate of the Cl-atom, `x_(2)` = r.
So, the coordinate of the centre of mass,
`x=(m_(1)x_(1)+m_(2)x_(2))/(m_(1)+m_(2))=(m.0+35.5m.r)/(m+35.5 m)`
`(35.5)/(36.5)r=(35.5)/(36.5)xx1.27xx10^(-10)=1.235xx10^(-10)`m.