Answer:
0.00493 m/s
Explanation:
T = Temperature of the isotope = 85 nK
R = Gas constant = 8.341 J/mol K
M = Molar mass of isotope = 86.91 g/mol
Root Mean Square speed is given by
[tex]v_r=\sqrt{\dfrac{3RT}{M}}\\\Rightarrow v_r=\sqrt{\dfrac{3\times 8.314\times 85\times 10^{-9}}{86.91\times 10^{-3}}}\\\Rightarrow v_r=0.00493\ m/s[/tex]
The Root Mean Square speed is 0.00493 m/s