Explanation​:
Using the Arrhenius equation k = Ae−Ea/RT, a linear relationship will be created by graphing ln k vs. 1/T​

Explanation​:
Both sides of the equation have the same number of gaseous moles, so the equilibrium position is unaffected by changes in pressure.

Explanation:​
The number of molecules remains constant. Temperature only changes the particles’ kinetic energy; when temperature increases, the kinetic energy of the particles also increases.

Explanation:
Using trials 1 and 2, as [X] doubles, rate also doubles therefore first order with respect to [X].
Using trials 2 and 3, as [Y] halves, rate stays the same and so, zero order with respect to [Y].
This gives a slow step that depends on unimolecular X, and not Y.

Explanation:
The endothermic reaction is favoured when the temperature increases. The concentration of products increases at t=10 mins; therefore, the forward reaction must be endothermic.
Increasing the volume decreases the pressure and causes the side with more moles of gas to be favoured. The concentration of reactants increases at t=15 mins; therefore, the reactants must have more moles of gas than the products.

Explanation:​
The rate constant increases with increasing A and decreases with increasing Ea​.
This question is on the lower end of the medium-difficulty category as students should be familiar with the effect of these variables on $k$, and are given the equation for assistance if needed.

Explanation:​
Students should be aware of the definition of frequency factor. However, questions on this topic are somewhat uncommon, and students could confuse this concept with the idea that molecules capable of successful collision lie above Ea​ in a Boltzmann distribution (leading them to select option D). The difficulty level is therefore at the higher end of the “easy” range.

Therefore, 0.5 moles of H2require 0.167 moles of N2 to completely react. There are $s$ of N2NX2​ available so N2 is the reactant in excess.

Explanation​:
The molecularity is given by the power to which the species is raised to in the rate expression. X is raised to the power of two meaning the rate determining step involves two X molecules.

Explanation​:
Rate is directly proportional to the concentration of $M$ as it is first order. As the concentration of $M$ has been multiplied by 1.5, the rate (0.5 s−1) must also be multiplied by 1.5.

Explanation​:

The theoretical yield is the maximum amount of product that will be formed if the limiting reagent is consumed completely.

Explanation​:
The peaks represent transition states where energy is at its highest. This graph shows a multi-step mechanism where Y is an intermediate species between R and P. Catalysts lower the activation energy which is the difference between R and X.

Explanation​:
$)$.
If $\Delta G$ is positive, ln(K) must be negative. ln(K) is negative for values smaller than 1.
A positive $\Delta G$ value indicates that the reaction is not spontaneous. Therefore, the equilibrium concentrations of the reactants are larger than the ones of the products; the equilibrium constant is less than 1.

Explanation​:
Increasing the volume decreases the pressure which shifts the position of the equilibrium to the right where there are more moles of gas.
The forward reaction is endothermic and so increasing the temperature favors this reaction.
A catalyst affects both the rate of the forward and reverse reactions equally and has no effect on the equilibrium yield.

Explanation:​
The rate constant, $k$, is the feature of the rate equation that is affected by temperature according to the Arrhenius equation k=Ae−Ea/RT.
The graph of rate vs temperature always shows this general trend, and similar questions have been asked several times in past papers.
The question is of moderate difficulty as the use of a specific example and reference to rate rather than k may derail some students. Confusion with the Arrhenius plot could also lead students to select option B.

Explanation​:

Kc​ is written as the concentrations of the products divided by the concentrations of the reactants each raised to the power of the coefficient in the balanced equation.

Explanation:​
Four factors that can increase the rate of a chemical reaction are: increasing the temperature of the reaction, adding a catalyst, increasing the concentration of the reactants and decreasing the solid particle size of the reactants.

Explanation:​
The $ln(2)$ term appears because k1​ is double k2​, and the factor of 1000 appears in the denominator to convert J mol−1to kJ mol−1.
Option B is almost correct, but the temperature terms 1/298​ and 1/308​ would need to be swapped to give a positive value for the activation energy.
The question is in the “hard” or “very hard” category since students must be able to identify the correct terms in the question for use in the equation, rearrange the equation correctly, and also perform a unit conversion.

Explanation​:
Units for $k$ are determined by dividing the units of rate by the units of the concentrations raised to their respective powers.
For a 3rd order reaction, k=mol dm−3 s−1/mol3 dm−9 = mol−2 dm6 s−1.

Explanation:​
The y-intercept = $lnA$ so must be larger for reaction 1.
The gradient (slope) is equal to −Ea/R​​ so, must be shallower (less negative) for reaction 1.
The question is in the “hard” category as students must know how to interpret an Arrhenius plot (or correctly interpret the given equation) and compare two reactions graphically.

Explanation:​
Adding water will reduce the concentration (dilution), and, therefore the frequency of effective collisions will decrease.