Chemical Kinetics

For the general reaction $aA + bB \rightarrow cC + dD$, the rate of reaction is expressed as:

Which of the following is true for a reaction rate?

If the rate of appearance of $NO_2$ is $0.012\ mol\ L^{-1} s^{-1}$ in the reaction $2N_2O_5 \rightarrow 4NO_2 + O_2$, what is the rate of the reaction?

In the reaction $A + 3B \rightarrow 2C + D$, the rate of disappearance of $B$ is:

Which of the following does NOT affect the rate constant of a reaction?

The value of the rate constant for a reaction is $k = 2 \times 10^{-3}\ mol^{-2}\ L^{2}\ s^{-1}$. The overall order of the reaction is:

For a zero-order reaction, the slope of the graph between the concentration of reactant and time is:

For a reaction $3A \rightarrow 2B$, the rate of reaction $+\frac{d[B]}{dt}$ is equal to:

A reaction is $50\%$ complete in 2 hours and $75\%$ complete in 4 hours. The order of the reaction is:

The rate constant for a reaction is $1.5 \times 10^{-2}\ s^{-1}$ at $300\ K$ and $4.5 \times 10^{-2}\ s^{-1}$ at $310\ K$. What is the temperature coefficient of the reaction?

Which of the following is true for an exothermic reaction when a catalyst is added?

What happens to a catalyst at the end of a chemical reaction?

In the reaction $2NO + O_2 \\rightarrow 2NO_2$, if the volume of the reaction vessel is halved, the rate of reaction will:

A reaction with a very high activation energy at room temperature is likely to be:

Which of the following is true for a reaction with a very large activation energy?

Which statement best describes the effect of increasing the intensity of light on the rate of a photochemical reaction?

If a reaction is spontaneous and exothermic, which of the following must be true about its activation energy?

The rate of a reaction is doubled for every $10^{\circ}C$ rise in temperature. The increase in reaction rate is mainly due to:

If the concentration of a reactant is increased, the rate of reaction increases. According to Collision Theory, this is because:

A reaction has a rate constant of $1.5 \times 10^{-4} \text{ s}^{-1}$ at $300\text{ K}$ and $4.5 \times 10^{-4} \text{ s}^{-1}$ at $310\text{ K}$. The activation energy $E_a$ is approximately:

A termolecular reaction involves the simultaneous collision of how many reacting species?

For the complex reaction $2NO_2 + F_2 \rightarrow 2NO_2F$, the rate law is $Rate = k[NO_2][F_2]$. What is the molecularity of the rate-determining step?

The overall order of a reaction can be found by adding:

The reaction $2HI \rightarrow H_2 + I_2$ (in gas phase) is a:

The rate constant for a reaction is $k = 2.0 \times 10^{-6} \text{ mol}^{-1} \text{ L s}^{-1}$. What is the overall order of the reaction?

In a reaction $A \rightarrow Products$, the rate doubles when the concentration of $A$ is increased by four times. The order of the reaction is:

The radioactive decay of unstable nuclei is an example of:

For the reaction $2NO(g) + Cl_{2}(g) \rightarrow 2NOCl(g)$, the rate law is $r = k[NO]^{2}[Cl_{2}]$. What is the order with respect to $NO$ and the overall order?

A reaction $A \rightarrow B$ has a rate constant $k = 1.2 \times 10^{-2}\ s^{-1}$. What is the order and molecularity of this reaction if it is elementary?

For a reaction $A + B \rightarrow Products$, the rate law is $r = k[A][B]$. If $A$ is present in large excess, the reaction follows:

For a zero-order reaction, the concentration of a reactant decreases from an initial value of $c$ to a final value of $c/4$ in time $t$ as illustrated in the following diagram. Which of the following is the correct expression for the rate constant $k$?

For a first-order reaction, the time for $90\%$ completion is approximately how many times the time for $50\%$ completion?

Which of the following is not a characteristic of a first-order reaction?

For a zero-order reaction, if the initial concentration is $a$ and the rate constant is $k$, the time taken for the reaction to be $50\%$ complete is:

Which of the following plots is NOT linear for a first-order reaction?

For a reaction $A+B \rightarrow C$, if it follows zero-order kinetics, what is the rate equation?

If $t_{99.9\%}$ is the time required for $99.9\%$ completion of a first-order reaction, then which relation is correct?

A first-order reaction $A \rightarrow B$ has a rate constant $k = 10^{-3}\text{ s}^{-1}$. If $[A]_0 = 1.0\text{ M}$, the rate of reaction when $50\%$ of $A$ has reacted is:

For a zero-order reaction, $t_{1/2}$ is 100 s. The time for $80\%$ completion is:

Which of the following units represents the rate constant for a zero-order reaction?

The ratio of the time required for $99.9\%$ completion to the time required for $50\%$ completion for a first-order reaction is:

If a reaction $A \to P$ follows zero-order kinetics, then a plot of $[A]$ versus time ($t$) will be a straight line with a slope equal to:

The time required for $93.75\%$ completion of a first-order reaction is how many times the half-life?

For a first-order gaseous reaction, if the initial pressure is $P_0$, the half-life $t_{1/2}$ is:

Consider two different chemical reactions: Reaction X, which follows zero-order kinetics, and Reaction Y, which follows first-order kinetics. Both reactions are observed to have the same half-life ($t_{1/2}$) when started with an initial reactant concentration of $2.0 \text{ M}$. If the initial concentration of both reactants is increased to $4.0 \text{ M}$ while keeping the temperature and rate constants unchanged, what is the relationship between the new half-life of X, $t_{1/2}(X)$, and the new half-life of Y, $t_{1/2}(Y)$?

A first-order reaction has $k = 4.62 \times 10^{-4} \text{ s}^{-1}$. Calculate the time in seconds for the concentration to reduce to half its initial value.

What percentage of a reactant will have decomposed after a period equal to two half-lives in a first-order reaction?

In a first-order reaction, the time required for $63.2\%$ completion is equal to the reciprocal of the rate constant ($1/k$). This time is also known as:

If the rate constant $k$ of a reaction is $1.6 \times 10^{-3} \text{ mol}^{-1} \text{ L s}^{-1}$, the time required for the concentration to drop from $1.0 \text{ M}$ to $0.5 \text{ M}$ is:

A first-order reaction $A \rightarrow B$ has $k = 10^{-3} \text{ s}^{-1}$. If $[A]_0 = 1.0 \text{ M}$, what is the rate of the reaction at $t = t_{1/2}$?

In collision theory, the rate constant $k$ is primarily determined by:

Which of the following is NOT a requirement for a collision to result in a reaction?

Which factor deals with the geometry of the colliding molecules?

Effective collisions are those which result in:

Which of the following is true for a reaction with a very low activation energy?

The concept of 'Threshold Energy' is most closely related to which part of the collision process?

According to collision theory, if the collision frequency $Z_{AB}$ is $10^{30}$, the steric factor $P$ is $0.1$, and the fraction of molecules with $E > E_a$ is $10^{-5}$, what is the reaction rate in terms of collisions per unit volume per second?

In the collision theory equation for the rate constant $k$, if we plot $\ln(k/\sqrt{T})$ against $1/T$, what will be the slope of the resulting straight line?

Which statement best describes the difference between Collision Theory and Transition State Theory (TST)?

Consider the reaction between $K$ atoms and $Br_2$ molecules. The experimental rate is actually higher than the rate calculated by simple collision theory ($P > 1$). This 'harpoon mechanism' is an exception caused by:

A catalyst increases the rate of the forward reaction by $10$ times. What is its effect on the rate of the backward reaction?

The frequency factor ($A$) depends on which of the following?

The energy needed to break the bonds of reactants is part of the:

Which statement correctly describes the activation energy of a fast reaction?

For a hypothetical reaction, the activation energy of the forward reaction is $150\text{ kJ/mol}$ and that of the backward reaction is $120\text{ kJ/mol}$. The reaction is:

According to the Arrhenius equation, the rate constant $k$ is related to temperature $T$ as $k = A e^{-E_a/RT}$. What happens as $T$ approaches infinity?

If the activation energy for a reaction is $100\text{ kJ/mol}$, what is the effect of adding a catalyst that lowers the $E_a$ to $80\text{ kJ/mol}$?

The value of the rate constant for a reaction is $1.6 \times 10^{-5}\text{ s}^{-1}$ at $300\text{ K}$ and $6.4 \times 10^{-5}\text{ s}^{-1}$ at $320\text{ K}$. What is $E_a$?

For a reaction, $k = 10^{15} e^{-2000/T}$. What is the value of $\log A$?

Which of the following is true for a reaction with high activation energy?

What is the relationship between the activation energy of the forward reaction ($E_{af}$) and the backward reaction ($E_{ab}$) for an endothermic reaction?

The pre-exponential factor ($A$) has the same units as the rate constant because the term $e^{-E_a/RT}$ is:

A catalyst increases the rate of reaction by providing an alternative pathway which has:

Which of the following terms in the Arrhenius equation accounts for the orientation of the molecules?

If the rate of a reaction becomes four times when the temperature is increased from $293\,K$ to $313\,K$, calculate the energy of activation. (Given $\log 2 = 0.301$ and $R = 8.314\,J\,K^{-1}\,mol^{-1}$)

Why does a rise in temperature usually increase the rate of reaction more than can be explained by the increase in collision frequency alone?

For a reaction, the rate constant $k$ is given by $\log k = 14 - \frac{10^4}{T}$. The activation energy $E_a$ for this reaction is:

Which of the following would result in a straight line for an Arrhenius plot?

The activation energy of a reaction is $75\,kJ/mol$. What is the ratio of rate constants $k_{400K}/k_{300K}$? (Use $R = 8.314\,J/K/mol$)

The slope of the line in a plot of $\ln(1/t)$ vs $1/T$ for a fixed degree of completion of a reaction is $-E_a/R$. This statement is: