A reaction has a rate constant of 2.08 × 10−4 s−1 at 26 oC and 0.394 s−1 at 79 oC . Determine the activation barrier for the reaction. Enter your answer numerically and in terms of kJ/mol

The activation energy of the reaction is 124.6 kJ/mol

Explanation:

To calculate activation energy of the reaction, we use Arrhenius equation, which is:

where,

= equilibrium constant at 79°C =

= equilibrium constant at 26°C =

= Activation energy of the reaction = ?

R = Gas constant = 8.314 J/mol K

= initial temperature =

= final temperature =

Putting values in above equation, we get:

Hence, the activation energy of the reaction is 124.6 kJ/mol

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%