In a parallel reaction in which two products can be formed from the same reactant, what determines the extent to which one product will be formed over another?

For each of the following reaction diagrams, estimate the activation energy $\left(E_{\mathrm{a}}\right)$ of the reaction: (a) Extent of reaction (b) Extent of reaction

The rate constant for the decomposition of acetaldehyde, $\mathrm{CH}_3 \mathrm{CHO}$, to methane, $\mathrm{CH}_4$, and carbon monoxide, $\mathrm{CO}$, in the gas phase is $1.1 \times 10^{-2} \mathrm{~L} \mathrm{~mol}^{-1} \mathrm{~s}^{-1}$ at $703 \mathrm{~K}^{\text {and }} 4.95 \mathrm{~L} \mathrm{~mol}^{-1} \mathrm{~s}^{-1}$ at $865 \mathrm{~K}$. Determine the activation energy for this decomposition.

Given the following values for the changes in enthalpy ($\Delta$ H) and entropy ($\Delta$ S), which of the following processes can take place at 298 K without violating the Second Law of Thermodynamics?

(a) $\Delta$ H = -84 kJ mol$^{-1}$ (-20 kcal mol$^{-1}$),

$\Delta$ S=+125 J mol$^{-1}$ K$^{-1}$(+30 cal mol$^{-1}$ K$^{-1}$)

(b) $\Delta$ H= -84 kJ mol$^{-1}$ (-20 kcal mol$^{-1}$),

$\Delta$ S= -125 J mol$^{-1}$ K$^{-1}$ (-30 cal mol$^{-1}$ K$^{-1}$)

(c) $\Delta$ H= +84 kJ mol$^{-1}$ (+20 kcal mol$^{-1}$),

$\Delta$ S= -125 J mol$^{-1}$ K$^{-1}$ (+30 cal mol$^{-1}$ K$^{-1}$)

(d) $\Delta$ H= +84 kJ mol$^{-1}$ (+20 kcal mol$^{-1}$),

$\Delta$ S= -125 J mol$^{-1}$ K$^{-1}$ (-30 cal mol$^{-1}$ K$^{-1}$)

What is a half-life? Is the half-life for a first-order reaction dependent on concentration?

The following reaction reaches equilibrium at $350^\circ C$ and 3 bar: $\mathrm{CH}_{3} \mathrm{CHO}(g)+\mathrm{H}_{2}(g) \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(g)$ If the system initially contains 1.5 mol $H_2$ for each mole of acetaldehyde, what is the composition of the system at equilibrium? What would be the effect of reducing the pressure to 1 bar? Assume ideal gases.

What is the difference between a first-order reaction and a second-order reaction?

What is the method of initial rates, and why is it used in chemical kinetics studies?

What is the difference between the order of a reaction with respect to a given species and the overall order?

Why is the stoichiometry of a reaction generally not sufficient to determine reaction order?

What is a transition state? How is the concept of a transition state used in activated complex theory?

A certain reaction is first order, and $540 \mathrm{~s}$ after initiation of the reaction, $32.5 \%$ of the reactant remains. a. What is the rate constant for this reaction? b. At what time after initiation of the reaction will $10 \%$ of the reactant remain?

What is the steady-state approximation, and when is this approximation employed?

Consider the schematic reaction A $\stackrel{k}{\rightarrow}$ P. a. If the reaction is one-half order with respect to A, what is the integrated rate law expression for this reaction? b. What plot would you construct to determine the rate constant $k$ for the reaction? c. What would be the half-life for this reaction? Will it depend on initial concentration of the reactant?