SCSA Chemistry Chemical equilibrium systems

Increased atmospheric carbon dioxide contributes to the greenhouse effect and global warming, which causes ocean temperatures to rise, not cool.

While the oceans will become more acidic due to increased carbon dioxide absorption, an increase in acidity corresponds to a decrease in pH, not an increase.

Ocean acidification increases the concentration of hydrogen ions, which react with carbonate ions to form bicarbonate, thereby decreasing the availability of carbonate ions for marine organisms.

This equilibrium determines the concentration of carbonate ions ($CO_3^{2-}$). Increased ocean acidity shifts this reaction to the left, reducing the carbonate available for marine organisms to build strong shells.

This reaction shows carbon dioxide dissolving in water to form carbonic acid, which is the primary driver of ocean acidification that ultimately impairs shell building.

This reaction shows the dissociation of carbonic acid into bicarbonate and hydronium ions, which increases ocean acidity and leads to a reduction in the carbonate ions needed for shell building.

This is incorrect because the stoichiometric coefficient of the reactant (2) must be used as an exponent, not a multiplier. The correct term is $[\text{HI}]^2$, not $2[\text{HI}]$.

This is incorrect because it uses atomic species (H, I) instead of the molecular species ($\text{H}_2$, $\text{I}_2$) actually present in the reaction, and it treats coefficients as multipliers rather than exponents.

This is incorrect because it substitutes atomic concentrations for molecular products and uses coefficients as multipliers in the numerator.

This option is incorrect because Statement I is false. The production of biofuels can damage the environment through deforestation, habitat destruction, and the use of agricultural fertilizers.

This option is incorrect because Statement I is false. While Statement II is true, biofuel production is not entirely harmless to the environment.

This option is incorrect because both Statements I and III are false. Fossil fuels are considered non-renewable because they take millions of years to form, unlike biofuels which can be replenished relatively quickly.

This value is $(K_c)^2$, which would be the equilibrium constant if the first reaction were multiplied by 2 but not reversed.

This value is $2 \times K_c$. When a reaction is multiplied by a coefficient, the equilibrium constant must be raised to that power, not multiplied by it.

This value results from incorrect mathematical manipulation of the equilibrium constant. The correct operation is to take the inverse square of the original $K_c$.

While statements I and II are correct, statement III is also true because both coal seam gas and petroleum gas are formed from ancient organic matter, making them fossil fuels.

While statements I and III are correct, statement II is also true because both gases are primarily composed of hydrocarbons, which produce carbon dioxide and water upon combustion.

While statements II and III are correct, statement I is also true because both gases are mixtures of various hydrocarbons and other trace gases, rather than pure substances.

While increasing the partial pressure of a reactant does increase the yield, it also increases (rather than decreases) the reaction rate due to a higher frequency of molecular collisions.

Increasing temperature increases the kinetic energy of the molecules, which always leads to an increase in the reaction rate, not a decrease.

The reaction forming $NO_2$ is exothermic; therefore, increasing the temperature shifts the equilibrium toward the reactants (left), decreasing the yield of $NO_2$.

If the rate of evaporation were less than the rate of condensation, the amount of liquid water would increase, causing the water level to rise.

If the rate of evaporation were greater than the rate of condensation, the amount of liquid water would decrease, causing the water level to drop.

While the rates are equal, they are not zero because molecules are constantly escaping and returning to the liquid surface in a state of dynamic equilibrium.

This option incorrectly assumes the iodide concentration is $2 \times 0.1$ and fails to square the iodide concentration in the $K_{sp}$ expression.

This option incorrectly assumes the iodide concentration from NaI is $2 \times 0.1$. NaI only produces one iodide ion per formula unit, so the initial $[\text{I}^-]$ is $0.1 \text{ mol L}^{-1}$.

This option forgets to square the iodide concentration. The $K_{sp}$ expression for $\text{PbI}_2$ is $[\text{Pb}^{2+}][\text{I}^-]^2$, so the denominator must be squared.

This is a true characteristic of dynamic equilibrium. The system is "dynamic" precisely because both the forward and reverse reactions continue to occur.

This is a true characteristic. The fundamental definition of dynamic equilibrium is that the forward and reverse reaction rates are exactly equal.

This is a true characteristic. According to Le Chatelier's principle, changing the temperature of a system at equilibrium will shift its position to favor either the endothermic or exothermic direction.

While combustion is highly exothermic, exothermicity alone does not make a reaction irreversible. Many reversible reactions have exothermic forward reactions.

In a combustion reaction, the products ($\text{CO}_2$ and $\text{H}_2\text{O}$) are actually more stable than the reactants, which is why the reaction releases energy.

While adding a reactant like oxygen favors the forward reaction according to Le Chatelier's principle, this describes shifting an equilibrium rather than defining a reaction as irreversible.

Equal concentrations of reactants and products do not generally occur at equilibrium, especially when the equilibrium constant $K_c$ is significantly different from 1.

A greater concentration of reactants than products would only be expected if the equilibrium constant $K_c$ was much less than 1, indicating a reactant-favored system.

The coefficients in the balanced chemical equation dictate the stoichiometric ratio in which substances react and form, not their absolute concentrations at equilibrium.