Question

Calculate the rms speed of helium atom at 27 degree celsius

Answer 1

The root mean square (RMS) speed of a gas molecule is the function of its temperature and is given by

rms = √3kT/m

k = Boltzmann constant

= 1.38×10−23

m = mass of one atom

T = Absolute temperature of the gas

Hope this helps you ☺️⭐✨✨⭐✌️✌️

Answer 2

Remember that

1 J

=

1 kg

⋅

m

2

/s

2

, which explains why

M

m

is in

kg/mol

.

υ

RMS

=

√

3

R

T

M

m

=

√

3

(

8.314472 J/mol

⋅

K

)

(

295 K

)

4.0026

×

10

−

3

kg/mol

=

















⎷

3

(

8.314472

kg

⋅

m

2

/s

2

⋅

mol

⋅

K

)

(

295

K

)

4.0026

×

10

−

3

kg

/

mol

=

1355.87 m/s

Or to three sig figs,

=

1360 m/s