Calculate the root mean square velocity of f2,cl2, and br2 at 304 k .

V(rms) = √(3RT/M)
Where R is the molar gas constant with value 8.314 and T is the temperature in Kelvin and M is the molar mass
v(rms F₂) = √(3 x 8.314 x 304 / 38)
v(rms F₂) = 14.1 m/s

v(rms Cl₂) = √(3 x 8.314 x 304 / 71)
v(rms Cl₂) = 10.3 m/s

v(rms Br₂) = √(3 x 8.314 x 304 / 160)
v(rms Br₂) = 6.88 m/s

29.1-12=17.1the answer is this one