Chapter 5

How can you determine whether a reaction is at chemical equilibrium?

How would you define the reaction rate? Which factors can affect it?

What is the difference between a global reaction rate expression and one based on elementary reactions?

At a certain temperature, why can a certain reaction have multiple values of the equilibrium constant?

What is the difference between \(K_{c} K_{p}\), and \(K_{x}\) ? For a gas-phase reaction, what is the relation between them?

Find the relation between \(K_{p}\) and \(K_{c}\) for the following gas-phase reaction: \(a \mathrm{~A}+b \mathrm{~B} \rightleftarrows c \mathrm{C}+d \mathrm{D}\)

For a reaction taking place at constant \(p\) and \(\mathrm{T}\), why can we say that the \(\Delta \mathrm{G}^{0}\) remains constant, but we cannot say the same for \(\Delta G\) ?

Qualitatively plot \(K_{c}\) versus the temperature for an endothermic and an exothermic reaction.

Why do catalysts not influence the chemical equilibrium?

In a container with a volumetric capacity of \(1 \mathrm{~L}\), we leave \(0.05 \mathrm{~mol}\) of \(\mathrm{PCl}_{5}\) and \(5 \mathrm{~mol}\) of \(\mathrm{PCl}_{3}\) reacting at \(760 \mathrm{~K}\). At equilibrium, we have \(0.043 \mathrm{~mol}\) of \(\mathrm{Cl}_{2}\). Find \(K_{c}\) for the reaction \(\mathrm{PCl}_{5} \rightleftarrows \mathrm{PCl}_{3}+\mathrm{Cl}_{2}\).

Explain the difference between homogeneous and heterogeneous catalysis.

A container with a capacity of \(1 \mathrm{~L}\) holds \(3 \mathrm{~mol}\) of \(\mathrm{N}_{2} \mathrm{O}_{4}\) at \(343 \mathrm{~K}\). At this temperature, the dissociation grade is \(65 \%\). Find \(K_{p}\) for the reaction \(\mathrm{N}_{2} \mathrm{O}_{4} \rightleftarrows\) \(2 \mathrm{NO}_{2}\).

Does the catalyst concentration affect the reaction rate?

At \(450^{\circ} \mathrm{C}\), the equilibrium constant for the reaction \(2 \mathrm{HI} \rightleftarrows \mathrm{H}_{2}+\mathrm{I}_{2}\) is \(K_{p}=50\). Find the dissociation grade of HI.