Skip to main content
Ch.15 - Chemical Equilibrium
Chapter 15, Problem 151a

The F-F bond in F2 is relatively weak because the lone pairs of electrons on one F atom repel the lone pairs on the other F atom; Kp = 7.83 at 1500 K for the reaction F2(g) ⇌ 2 F(g). (a) If the equilibrium partial pressure of F2 molecules at 1500 K is 0.200 atm, what is the equilibrium partial pressure of F atoms in atm?

Verified step by step guidance
1
Start by writing the expression for the equilibrium constant Kp for the reaction F2(g) ⇌ 2 F(g). The expression is Kp = (P_F)^2 / P_F2, where P_F is the partial pressure of F atoms and P_F2 is the partial pressure of F2 molecules.
Substitute the given values into the Kp expression. You know that Kp = 7.83 and P_F2 = 0.200 atm. So, the equation becomes 7.83 = (P_F)^2 / 0.200.
Rearrange the equation to solve for (P_F)^2. Multiply both sides by 0.200 to get (P_F)^2 = 7.83 * 0.200.
Take the square root of both sides to solve for P_F. This will give you P_F = sqrt(7.83 * 0.200).
Calculate the value of P_F using the expression from the previous step to find the equilibrium partial pressure of F atoms in atm.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

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

Equilibrium Constant (Kp)

The equilibrium constant, Kp, is a measure of the ratio of the partial pressures of products to reactants at equilibrium for a given reaction at a specific temperature. For the reaction F2(g) ⇌ 2 F(g), Kp = 7.83 indicates that at 1500 K, the ratio of the pressure of F atoms squared to the pressure of F2 is constant. Understanding Kp is essential for calculating the equilibrium concentrations or pressures of the species involved.
Recommended video:
Guided course
03:20
Equilibrium Constant Expressions

Partial Pressure

Partial pressure is the pressure exerted by a single component of a gas mixture. In the context of the reaction, the total pressure is the sum of the partial pressures of F2 and F atoms. By knowing the partial pressure of F2 at equilibrium, one can use the equilibrium constant to find the partial pressures of the other species, which is crucial for solving the problem.
Recommended video:
Guided course
00:48
Partial Pressure Calculation

Stoichiometry of the Reaction

Stoichiometry refers to the quantitative relationship between reactants and products in a chemical reaction. In the given reaction, the stoichiometry indicates that one mole of F2 produces two moles of F atoms. This relationship is vital for determining how changes in the concentration or pressure of one species affect the others at equilibrium, allowing for the calculation of the equilibrium partial pressure of F atoms based on the given conditions.
Recommended video:
Guided course
01:16
Stoichiometry Concept
Related Practice
Textbook Question
At 1000 K, Kp = 2.1 * 106 and ΔH° = - 107.7 kJ for the reaction H21g2 + Br21g2 ∆ 2 HBr1g2.(b) For the equilibrium in part (a), each of the following changes will increase the equilibrium partial pressure of HBr. Choose the change that will cause the greatest increase in the pressure of HBr, and explain your choice.(ii) Adding 0.10 mol of Br2
486
views
Textbook Question
Halogen lamps are ordinary tungsten filament lamps in which the lamp bulb contains a small amount of a halogen (often bromine). At the high temperatures of the lamp, the halogens dissociate and exist as single atoms.(c) When the WBr41g2 diffuses back toward the filament, it decomposes, depositing tungsten back onto the fila- ment. Show quantitatively that the pressure of WBr4 from part (a) will cause the reaction in part (a) to go in reverse direction at 2800 K. [The pressure of Br1g2 is still 0.010 atm.] Thus, tungsten is continually recycled from the walls of the bulb back to the filament, allow-ing the bulb to last longer and burn brighter.
328
views
Textbook Question

The F-F bond in F2 is relatively weak because the lone pairs of electrons on one F atom repel the lone pairs on the other F atom; Kp = 7.83 at 1500 K for the reaction F2(g) ⇌ 2 F(g). (b) What fraction of the F2 molecules dissociate at 1500 K?

300
views
Textbook Question

The F-F bond in F2 is relatively weak because the lone pairs of electrons on one F atom repel the lone pairs on the other F atom; Kp = 7.83 at 1500 K for the reaction F2(g) ⇌ 2 F(g). (c) Why is the F-F bond in F2 weaker than the Cl-Cl bond in Cl2?

1354
views