A certain reaction has an activation energy of #"62.0 kJ/mol"# and a frequency factor of #7.50 xx 10^12 "M"^(-1)"s"^(-1)# at #27^@ "C"#. What is the rate constant?

1 Answer
Truong-Son N.
Nov 27, 2017

The rate constant is found from the Arrhenius equation.

#k = Ae^(-E_a//RT)#

where #A# is the frequency factor in the units of the rate constant, #E_a# is the activation energy, #R# is the universal gas constant in energy units, and #T# is the temperature in #"K"#.

The units in the exponential MUST cancel out. So, convert #R# to #"kJ/mol"cdot"K"# then proceed.

#"8.314472 J/mol"cdot"K" = "0.008314472 kJ/mol"cdot"K"#

Therefore:

#color(blue)(k) = 7.50 xx 10^12 "M"^(-1)"s"^(-1) cdot e^(-("62.0 kJ/mol")//("0.008314472 kJ/mol"cdot"K" cdot (24+"273.15 K"))#

#= color(blue)("94.8 M"^(-1)cdot"s"^(-1))#

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