At what temperature do hydrdogen molecule have the same rms speed as nitrogen molecule at 455 degree celsius

change temps to kelvins.

Now, if they have the same rms speed, temp is dependent on mass

Temp=constant*m (vrms)^2

TempH2=constant*2(Vrms)^2
TempN2=constant*28(vrms)^2

tempH2=constant*2(tempN2/(28*constant)

tempH2=(455+273)/14 Kelvins