Question

When the volume of a vessel containing a gaseous equilibrium system is decreased, the ____ of the gaseous substances present is initially increased.

Short answer

When the volume of a vessel containing a gaseous equilibrium system is decreased, the \(pressure\) of the gaseous substances present is initially increased.

Step-by-step solution

Understand the concept of a gaseous equilibrium system

A gaseous equilibrium system refers to a mixture of gases in which the rate of the forward reaction equals the rate of the reverse reaction, resulting in no net change in the concentrations of the reactants and products. In such a system, decreasing the volume of the vessel will cause some change in the properties of the gaseous substances involved.

Recall the ideal gas law

The ideal gas law relates the pressure (P), volume (V), temperature (T), and the amount (n) of a gas through the equation PV=nRT, where R is the ideal gas constant. In a gaseous equilibrium system, reducing the volume will impact the pressure of the gas.

Apply Le Chatelier's Principle

Le Chatelier's Principle states that if a change is made to a system in equilibrium, the system will respond in such a way as to counteract the change and restore equilibrium. Since decreasing the volume of the vessel will increase the pressure, the equilibrium system will adjust to minimize this change in pressure.

Find the missing word

From the ideal gas law and our understanding of Le Chatelier's Principle, we can see that decreasing the volume of a vessel containing a gaseous equilibrium system will initially increase the ____ of the gaseous substances present, where the blank should be filled with the word "pressure".

Key concepts

Le Chatelier's Principle

Understanding Le Chatelier's Principle is crucial when studying how equilibrium systems respond to changes in their conditions. This principle provides a qualitative prediction regarding the effect of external changes on a system at equilibrium.

The principle states that if you apply a change to a system in dynamic equilibrium, such as altering the concentration, pressure, or temperature, the equilibrium position will shift to oppose the change. Imagine a seesaw balanced perfectly in the middle. If you push down on one side, the other side goes up to counterbalance the change. This is analogous to what happens at a molecular level in a reaction at equilibrium.

In the context of the exercise, decreasing the vessel's volume increases the pressure, as molecules are now more compacted. According to Le Chatelier's Principle, the system will shift in a direction that reduces this increase in pressure. In a gaseous reaction involving different numbers of moles of reactants and products, this would often mean favoring the reaction that produces fewer gas molecules.

Ideal Gas Law

The Ideal Gas Law is a fundamental equation that bridges the gap between several properties of a gas. Given by the formula \( PV=nRT \), it describes the relationship amongst the pressure (P), volume (V), and temperature (T) of a gas, with 'n' representing the number of moles and 'R' the ideal gas constant.

This law implies that for a fixed amount of gas at a constant temperature, the pressure and volume of a gas are inversely related. In simpler terms, if you decrease the volume, the pressure goes up, assuming the temperature is kept constant. It's like squeezing a balloon—the air inside gets compressed and the pressure increases.

Understanding the Variables

• Pressure (P): Force exerted by the gas molecules against the container's surface.
• Volume (V): The space that the gas occupies.
• Temperature (T): Measures the average kinetic energy of the gas molecules. In the context of the Ideal Gas Law, it's always in Kelvins.
• Amount (n): The quantity of gas typically represented in moles.
• Ideal Gas Constant (R): It's a physical constant that relates energy units within the context of pressure-volume work.

Equilibrium Reaction Dynamics

Equilibrium reaction dynamics delve into what occurs at the molecular level when a chemical reaction reaches a state of equilibrium. At this point, the forward reaction—reactants transforming into products—and the reverse reaction—products reverting to reactants—occur at identical rates, leading to constant concentrations of all chemical species involved over time.

It's like having a bathtub with the tap running and the drain open. If the water flows in at the same rate it drains out, the water level stays the same—that's the dynamic part, even though the water level (the concentration of reactants and products) appears to not change. In practice, these reactions are never static, they're dynamic and constantly adjusting in micro ways to stay balanced.

In relation to the exercise, when the volume of the vessel decreases and hence the pressure increases, the reaction dynamics are disrupted. In accordance with Le Chatelier's Principle and accounting for the impact stated by the Ideal Gas Law, the system will seek a new equilibrium by adjusting the rates of the forward and reverse reactions accordingly.