Consider the following plots of rate constant versus $${1 \over T}$$ for four different reactions. Which of the following orders is correct for the activation energies of these reactions?

The rate of a certain biochemical reaction at physiological temperature (T) occurs 10⁶ times faster with enzyme than without. The change in the activation energy upon adding enzyme is :

For the reaction
2H₂(g) + 2NO(g) $$ \to $$ N₂(g) + 2H₂O(g)
the observed rate expression is, rate = K_f[NO]²[H₂]. The rate expression for the reverse reaction is :

NO₂ required for a reaction is produced by the decomposition of N₂O₅ in CCl₄ as per the equation,
2N₂O₅(g) $$ \to $$ 4NO₂(g) + O₂(g).
The initial concentration of N₂O₅ is 3.00 mol L^–1 and it is 2.75 mol L^–1 after 30 minutes. The rate of formation of NO₂ is :