Skip to main content
Ch.15 - Chemical Equilibrium
Chapter 15, Problem 7a

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO2(𝑠) ⇌ 2PbO(𝑠) + O2(𝑔). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true? a. There will be less PbO2 remaining in vessel A,

Verified step by step guidance
1
Step 1: Understand the chemical reaction. The decomposition of lead(IV) oxide (PbO2) is given by the equation: 2 PbO2(s) ⇌ 2 PbO(s) + O2(g). This is a reversible reaction where solid lead(IV) oxide decomposes into solid lead(II) oxide and gaseous oxygen.
Step 2: Consider the conditions of the reaction. Both vessels are heated to 400°C, which is above the decomposition temperature of 300°C. This means the reaction will proceed towards the formation of PbO and O2 until equilibrium is reached.
Step 3: Analyze the equilibrium state. At equilibrium, the rate of the forward reaction (decomposition of PbO2) equals the rate of the reverse reaction (formation of PbO2 from PbO and O2). The amounts of reactants and products remain constant at this point.
Step 4: Compare the initial conditions of the vessels. If the vessels have different initial amounts of PbO2, the equilibrium position may differ, but the equilibrium constant (K) remains the same at a given temperature. The statement about less PbO2 remaining in vessel A depends on the initial conditions and the equilibrium position.
Step 5: Evaluate the statement. To determine if there is less PbO2 in vessel A, consider the initial amounts and how they affect the equilibrium position. Without specific initial amounts, we cannot definitively say which vessel has less PbO2 remaining.

Verified Solution

Video duration:
57s
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In the context of the given reaction, heating the system affects the equilibrium position, potentially favoring the formation of products (PbO and O2) over the reactant (PbO2) depending on temperature changes.
Recommended video:
Guided course
04:21
Chemical Equilibrium Concepts

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust to counteract the change and restore a new equilibrium. In this case, increasing the temperature shifts the equilibrium position to favor the endothermic decomposition of PbO2 into PbO and O2, leading to a decrease in the amount of PbO2.
Recommended video:
Guided course
07:32
Le Chatelier's Principle

Thermodynamics of Reactions

The thermodynamics of a reaction involves understanding the energy changes associated with the reaction, including enthalpy and entropy. For the decomposition of PbO2, the reaction is endothermic, meaning it absorbs heat. As temperature increases, the reaction is driven forward, resulting in more PbO and O2 being produced, which is crucial for predicting the outcome in the sealed vessels.
Recommended video:
Guided course
01:18
First Law of Thermodynamics
Related Practice
Open Question
Consider the equilibrium Na2O(s) + SO2(g) ⇌ Na2SO3(s). (a) Write the equilibrium-constant expression for this reaction in terms of partial pressures. (b) All the compounds in this reaction are soluble in water. Rewrite the equilibrium-constant expression in terms of molarities for the aqueous reaction.
Textbook Question

The following diagram represents a reaction shown going to completion. Each molecule in the diagram represents 0.1 mol, and the volume of the box is 1.0 L. (d) Assuming that all of the molecules are in the gas phase, calculate n, the change in the number of gas molecules that accompanies the reaction. [Section 15.2]

600
views
Textbook Question

Ethene (C2H4) reacts with halogens (X2) by the following reaction:

C2H4(𝑔) + X2(𝑔) ⇌ C2H4X2(𝑔)

The following figures represent the concentrations at equilibrium at the same temperature when X2 is Cl2 (green), Br2 (brown), and I2 (purple). List the equilibria from smallest to largest equilibrium constant. [Section 15.3]

490
views
Textbook Question

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO2(𝑠)⇌2PbO(𝑠)+O2(𝑔). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true?

b. There will be less PbO2 remaining in vessel B,

714
views
Textbook Question

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO2(𝑠) ⇌ 2PbO(𝑠) + O2(𝑔). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true? (c) The amount of PbO2 remaining in each vessel will be the same. [Find more in Section 15.4]

304
views
Textbook Question

The reaction A2 + B2 ⇌ 2 AB has an equilibrium constant Kc = 1.5. The following diagrams represent reaction mixtures containing A2 molecules (red), B2 molecules (blue), and AB molecules. (a) Which reaction mixture is at equilibrium?

1344
views