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

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

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 correct balanced equation is:

2LiOH + H2​SO4​ → Li2​SO4​ + 2H2​O.

2+1+1+2 = 6

Explanation:​
D has the steepest gradient when a tangent is drawn.

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​:
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:​
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.

Explanation​:
The ratio of SO3:SO2:O2 is 2:2:1. Therefore, half the number of moles of oxygen would be produced compared to SO2​

Explanation​:
A dynamic equilibrium is reached in a closed system when the rates of the forward and reverse reactions are equal. The concentrations of reactants and products do not change but are non-stop being interconverted. The equilibrium could favor one side over the other.

Explanation:
The rate expression can only be determined experimentally.

Explanation:​
All graphs are [A] vs time.
A linear plot of [A] vs time represents a zero order reaction, B and D represent first order reactions (B represents [A] as a product and is therefore increasing).
C is a second order plot of [A] vs time and has a steeper initial rate (slope) when compared to first order reactions.

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​:
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​:
A catalyst provides an alternative pathway for the reaction lowering the activation energy. It affects both the forward and reverse reaction rates equally. The position of equilibrium will not change.

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​:

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:​
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​:
$)$.
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:
The balanced chemical equation is 2C3H7OH(l)+9 O2(g)→6 CO2(g)+8 H2O(l). The sum of the coefficients is $25$.

Explanation​:

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