what is the kinetic energy, in J, of

Question

a)an Ar atom moving w/ a speed of 650m/s

b)a mole of Ar atoms moving w/ a speed of 650m/s?

a) K.E. = (1/2) M V^2
For M, use the mass of an Argon atom. It equals 0.040 kg (40 g) divided by Avogadro's number. M must be in kg to get the K.E. in Joules

b) Multiply the (a) result by Avogadro's number.

thanx

Answer 1

a) K.E. = (1/2) (0.040 kg/6.022 x 10^23) (650 m/s)^2
= 1.9 x 10^-21 J

b) K.E. = (1.9 x 10^-21 J) (6.022 x 10^23)
= 1.1 x 10^3 J