Van der Waals constant 'b' for helium is `2.93 xx 10^(-5) m^(3) mol^(-1)`. Calculate actual volume of helium atom. What is the radius of helium atom?

Explanation

Excluded volume = `b = 4 xx (V_a xx N_0)`
where `V_a` is the actual volume of helium atom.
`V_a = (b)/(4N_0) = (2.93 xx 10^(-5))/(4 xx 6.022 xx 10^(23))`
`= 1.02 xx 10^(-29) m^3`
Volume of helium atom = `4/3 pi r^3`
Radius of helium atom, `r = 1.3 xx 10^(-10) m`.