Explanation:
The rate expression can only be determined experimentally.

Explanation​:
The equilibrium shifts to favor the endothermic reaction (forward) when the temperature is increased to resist that change (Le Chatelier’s principle).
Temperature is the only factor that changes the value of the equilibrium constant.

Explanation​:
The solid KI will dissolve until the solution is saturated and then a dynamic equilibrium will be established where the rate of precipitation is equal to the rate of dissolution of the excess solid.
The system must be closed and therefore no matter can be exchanged with the surroundings.

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​:
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​:
Graph D shows that rate is proportional to [A]2.
A and B are concentration-time graphs. C is a first order rate-concentration graph as they are directly proportional

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

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​:
Q>Kc, therefore the backward reaction will be favored as the system approaches dynamic equilibrium.
The backward reaction is endothermic, so the temperature will decrease.
There are more moles of gas on the left and so pressure increases. NO2​ is red-brown and so the gas mixture will get darker.

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

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:​
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:​
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​:
OH− ions react with the H+ ions, thus decreasing their concentration. The equilibrium shifts towards the reactants to produce more H+ and resist this change (Le Chatelier’s principle). This produces more yellow chromate ions.
The value of Kc is only affected by temperature so this is unchanged.

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

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