chap 13 pt 2

Questions and Answers

What happens to the total pressure in a container when the volume is decreased?

Total pressure remains constant regardless of volume change.

Total pressure decreases due to the exothermic nature of the reaction.

Total pressure decreases due to increased volume.

Total pressure increases due to increased concentration of gases. (correct)

According to Le Chatelier’s principle, how does an increase in pressure affect a reaction at equilibrium?

The reaction rate increases regardless of direction.

The equilibrium shifts to the side with fewer gas molecules. (correct)

The equilibrium shifts to the side with more gas molecules.

The equilibrium remains unchanged.

What effect does increasing temperature have on an endothermic reaction?

The equilibrium remains unchanged.

Decreases the equilibrium constant.

Shifts the equilibrium to the left, favoring reactants.

Shifts the equilibrium to the right, favoring products. (correct)

In an exothermic reaction, what happens when the temperature is decreased?

The equilibrium shifts to the right, favoring products. Signup and view all the answers

What role does heat play in an endothermic reaction?

Heat acts as a reactant. Signup and view all the answers

How does a decrease in volume affect the reaction equilibrium with respect to gas concentration?

Gas concentration increases, leading to a shift toward products. Signup and view all the answers

In the reaction CO + 3H2 ⇌ CH4 + H2O, what happens after compression if the equilibrium shifts?

The equilibrium shifts to the right, favoring products. Signup and view all the answers

What effect does increasing the temperature have on the equilibrium constant of an exothermic reaction?

The equilibrium constant decreases. Signup and view all the answers

What is the first step in calculating equilibrium concentrations?

Set up an ICE table with expressions in x Signup and view all the answers

How does adding reactants affect the position of equilibrium in a chemical reaction?

It shifts the equilibrium to the right, producing more products Signup and view all the answers

Which of the following methods does NOT alter the equilibrium composition of a gaseous reaction mixture?

Changing the shape of the vessel Signup and view all the answers

In the reaction CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g), what happens when additional products are added?

The equilibrium shifts to produce more reactants Signup and view all the answers

When using an ICE table, what do 'Initial', 'Change', and 'Equilibrium' refer to?

Concentrations at various points in time Signup and view all the answers

What does Le Chatelier’s principle describe?

How a system at equilibrium responds to disturbances Signup and view all the answers

If a gaseous reaction reduces in volume, what effect does this have on equilibrium?

The equilibrium always shifts to the side with fewer moles of gas Signup and view all the answers

In terms of equilibrium constant, what occurs when a chemical reaction reaches a new equilibrium after disturbance?

The equilibrium constant remains the same Signup and view all the answers

Study Notes

Calculating Equilibrium Concentrations

Use an ICE table (Initial, Change, Equilibrium) to organize data for calculations.
Define initial concentrations, changes in concentration, and final equilibrium concentrations using variable x.
Substitute these expressions into the equilibrium constant equation to solve for equilibrium concentrations.

Altering Equilibrium Composition

Changes to affect equilibrium composition in gas reactions:
- Add reactants or remove products to alter concentrations.
- Change volume to affect partial pressure of gases.
- Adjust temperature of the system.

Le Chatelier's Principle

A system at equilibrium will shift to counteract disturbances in concentration, temperature, or pressure.
Example reaction: CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g).
New equilibrium concentrations adjust to maintain the equilibrium constant.

Concentration Changes

Adding reactants or removing products shifts the equilibrium to the right, increasing product formation.
Adding products or removing reactants shifts the equilibrium to the left, increasing reactant formation.

Pressure Changes

Decreasing the container's volume increases gas concentration and pressure.
The equilibrium shifts towards the side with fewer gas molecules to relieve the pressure.
In the reaction CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g), compression shifts equilibrium to the right due to fewer gas molecules on that side.

Temperature Effects: Endothermic Reactions

Endothermic reactions require heat as a reactant and absorb energy.
Increasing temperature shifts equilibrium right, favoring products and increasing equilibrium constant.
Decreasing temperature shifts equilibrium left, favoring reactants and decreasing equilibrium constant.

Temperature Effects: Exothermic Reactions

Exothermic reactions release energy, with heat acting as a product.
Increasing temperature shifts equilibrium left, favoring reactants and decreasing equilibrium constant.
Decreasing temperature shifts equilibrium right, favoring products and increasing equilibrium constant.

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Description

Explore the principles of chemical equilibrium, including the use of ICE tables for calculating equilibrium concentrations and the effects of concentration changes on equilibrium composition. Learn how Le Chatelier's Principle helps predict shifts in equilibrium in response to external changes. This quiz will test your understanding of these key concepts in chemistry.