What is Le Ch$\^{a}$telier's principle? Consider the reaction $2 \mathrm{NOCl}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})+$ $\mathrm{Cl}_2(\mathrm{~g})$. If this reaction is at equilibrium, what happens when the following changes occur?

For this change, what happens to the value of $K$ for the reaction as equilibrium is reached again? Give an example of a reaction for which the addition or removal of one of the reactants or products has no effect on the equilibrium position.

$\mathrm{NOCl}(g)$ is removed.

In general, how will the equilibrium position of a gas-phase reaction be affected if the volume of the reaction vessel changes? Are there reactions that will not have their equilibria shifted by a change in volume? Explain. Why does changing the pressure in a rigid container by adding an inert gas not shift the equilibrium position for a gas-phase reaction?

What is Le Ch$\^{a}$telier's principle? Consider the reaction $2 \mathrm{NOCl}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})+$ $\mathrm{Cl}_2(\mathrm{~g})$. If this reaction is at equilibrium, what happens when the following changes occur?

For this change, what happens to the value of $K$ for the reaction as equilibrium is reached again? Give an example of a reaction for which the addition or removal of one of the reactants or products has no effect on the equilibrium position.

$\mathrm{NOCl}(\mathrm{g})$ is added.

In general, how will the equilibrium position of a gas-phase reaction be affected if the volume of the reaction vessel changes? Are there reactions that will not have their equilibria shifted by a change in volume? Explain. Why does changing the pressure in a rigid container by adding an inert gas not shift the equilibrium position for a gas-phase reaction?

The value of the equilibrium constant K depends on which of the following (more than one answer may be correct)? the initial concentrations of the reactants

Methanol, a common laboratory solvent, poses a threat of blindness or death if consumed in sufficient amounts. Once in the body, the substance is oxidized to produce formaldehyde (embalming fluid) and eventually formic acid. Both of these substances are also toxic in varying levels. The equilibrium between methanol and formaldehyde can be described as follows:

$$\mathrm{CH}_{3} \mathrm{OH}(a q) \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}(a q)+\mathrm{H}_{2}(a q)$$

Assuming the value of K for this reaction is $3.7 \times 10^{-10},$ what are the equilibrium concentrations of each species if you start with a 1.24 M solution of methanol? What will happen to the concentration of methanol as the formaldehyde is further converted to formic acid?

For the following endothermic reaction at equilibrium: $2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)$ which of the following changes will increase the value of K? adding a catalyst (constant T)

The creation of shells by mollusk species is a fascinating process. By utilizing the $\text{Ca}^{2+}$ in their food and aqueous environment, as well as some complex equilibrium processes, a hard calcium carbonate shell can be produced. One important equilibrium reaction in this complex process is

$$\text{HCO}_3^{-} (aq) \leftrightharpoons \text{H}^+ (aq) + \text{CO}_3^{2-} (aq)$$

K=$5.6 \times 10^{-11}$ of 0.16 mole $\text{HCO}_3^-$ is placed into 1.00 L of solution, what will be the equilibrium concentration of $\text{CO}_3^{2-}$?

For the reaction below, $K _ { p } = 1.16$ at $800 ^ { \circ } \mathrm { C }$

$$\mathrm { CaCO } _ { 3 } ( s ) \rightleftharpoons \mathrm { CaO } ( s ) + \mathrm { CO } _ { 2 } ( g )$$

If a 20.0-g sample of $\mathrm { CaCO } _ { 3 }$ is put into a $10.0 - \mathrm { L }$ container and heated to $800^\circ C,$ what percentage by mass of the $\mathrm { CaCO } _ { 3 }$ will react to reach equilibrium?

For the following endothermic reaction at equilibrium: $2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)$ which of the following changes will increase the value of K? adding $\mathrm{SO}_{2}(g)$ (constant T)

Peptide decomposition is one of the key processes of digestion, where a peptide bond is broken into an acid group and an amine group. We can describe this reaction as follows:

$$\text {Peptide}(aq)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \text {acid group}(aq)+\text {amine group}(aq)$$

If we place 1.0 mole of peptide into 1.0 L water, what will be the equilibrium concentrations of all species in this reaction? Assume the K value for this reaction is $3.1 \times 10^{-5}.$

Suppose $K=4.5 \times 10^{-3}$ at a certain temperature for the reaction

$$\mathrm{PCl}_{5}(g) \rightleftharpoons \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g)$$

If it is found that the concentration of $\mathrm{PCl}_{5}$ is twice the concentration of $\mathrm{PCl}_{3},$ what must be the concentration of $\mathrm{Cl}_{2}$ under these conditions?

For the following endothermic reaction at equilibrium: $2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)$ which of the following changes will increase the value of K? adding Ne(g) (constant T)

Many sugars undergo a process called mutarotation, in which the sugar molecules interconvert between two isomeric forms, finally reaching an equilibrium between them. This is true for the simple sugar glucose, $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6},$ which exists in solution in isomeric forms called alpha-glucose and beta-glucose. If a solution of glucose at a certain temperature is analyzed, and it is found that the concentration of alpha-glucose is twice the concentration of beta-glucose, what is the value of K for the interconversion reaction?

The synthesis of ammonia gas from nitrogen gas and hydrogen gas represents a classic case in which a knowledge of kinetics and equilibrium was used to make a desired chemical reaction economically feasible. Explain how each of the following conditions helps to maximize the yield of ammonia. running the reaction at high pressure

For the following endothermic reaction at equilibrium: $2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)$ which of the following changes will increase the value of K? decreasing the volume (constant T)