Question

1. If argon has an average velocity under certain conditions of 498 m/s, what is the average velocity of helium atoms under the same conditions?

2. How many times faster will the velocity of hydrogen molecule be than a molecule of carbon dioxide at the same temperature?

Answer 1

1)

vavg = k sqrt (T/M)

here : T is temperature in Kelvin

M is molar mass

If we take ratio, above expression becomes

vrms(He)/vrms(Ar) = sqrt (M(Ar)/M(He))

we have:

M(He) = 4.003 g/mol

M(Ar) = 39.95 g/mol

vrms(He)/vrms(Ar) = sqrt (39.95/4.003)

vrms(He)/vrms(Ar) = sqrt (9.98)

vrms(He)/vrms(Ar) = 3.1591

vrms(He)/498.0 = 3.1591

vrms(He) = 1573 m/s

Answer: 1570 m/s

2)

vavg = k sqrt (T/M)

here : T is temperature in Kelvin

M is molar mass

If we take ratio, above expression becomes

vrms(H2)/vrms(CO2) = sqrt (M(CO2)/M(H2))

we have:

M(H2) = 2.016 g/mol

M(CO2) = 44.01 g/mol

vrms(H2)/vrms(CO2) = sqrt (44.01/2.016)

vrms(H2)/vrms(CO2) = sqrt (21.8304)

vrms(H2)/vrms(CO2) = 4.6723

Answer: 4.67