For a hypothetical reaction $A \to B$, the activation energies for the forward and backward reactions are $19 \ kJ/mol$ and $9 \ kJ/mol$ respectively. The heat of reaction is $.... \ kJ/mol$.

The time required for $10 \%$ completion of a first order reaction at $298 \,K$ is equal to that required for its $25 \%$ completion at $308 \,K$. If the value of $A$ is $4 \times 10^{10} \,s^{-1}$,calculate $k$ at $318 \,K$ and $E_a$.

The rate constant of a reaction at $500 \ K$ and $700 \ K$ are $0.02 \ s^{-1}$ and $0.2 \ s^{-1}$ respectively. The activation energy of the reaction (in $kJ \ mol^{-1}$) is $(R=8.3 \ J \ K^{-1} \ mol^{-1})$

$A$ catalyst:

An egg takes $4.0 \text{ minutes}$ to boil at sea level where the boiling point of water is $T_1 \text{ K}$, whereas it takes $8.0 \text{ minutes}$ to boil on a mountain top where the boiling point of water is $T_2 \text{ K}$. The activation energy for the reaction that takes place during the boiling of an egg is:

The activation energy of a reaction can be determined from the slope of which of the following graphs?