Which of the following gas samples have the greatest average molecular speed at 25°C? A) Kr
B) CH4
C) N2
D) CH2CI2
E) CO2

We know

Lets find one by one

Option B is correct.

B) Methane, CH4

Explanation:

» For a molecule to have a great molecular speed, it mas have less molecular mass.

• From the samples given,

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.