which gas has molecules with the greatest average molecular speed at 25 C?






2 Answers

  • average speed = square root of (8RT/pi M)

    where R = gas constant = 8.314 J/K/mole

    T = temperature

    pi = 22/7 or 3.14

    M = molecular mass

    now since mass is in denominator ....it means molecular mass is inversely proportional to average speed ....so as mass increases average speed decreases.....and as mass decreases average speed increases

    so find out -which of the following has lightest molecular mass

    CH4 = 16 g/mole

    Kr = 83.8 g/mole

    N2 = 28 g/mole

    CO2 = 44 g/mole

    Ar = 39.9 g/mole

    since CH4 has lowest molecular mass among these so it's average speed will be highest...

    and the order of average speed for these gases in decreasing order will be :

    CH4 > N2 > Ar > CO2 > Kr

  • CH4 because its molar mass is the smallest

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts