Skip to main content
Ch.15 - Chemical Equilibrium
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoBrown 14th EditionCh.15 - Chemical EquilibriumProblema 19
Capitolo 15, Problema 19

Which of the following statements are true and which are false? (a) The equilibrium constant can never be a negative number. (b) In reactions that we draw with a single-headed arrow, the equilibrium constant has a value that is very close to zero.

Guida verificata passo dopo passo
1
Step 1: Understand the concept of the equilibrium constant (K). It is a ratio of the concentrations of products to reactants, each raised to the power of their stoichiometric coefficients, at equilibrium. The equilibrium constant is always a positive number because concentrations cannot be negative.
Step 2: Analyze statement (a): 'The equilibrium constant can never be a negative number.' Since concentrations are always positive, the equilibrium constant, which is a ratio of these concentrations, must also be positive. Therefore, statement (a) is true.
Step 3: Consider the meaning of a single-headed arrow in chemical reactions. A single-headed arrow indicates a reaction that goes to completion, meaning the reactants are fully converted to products, and the reverse reaction is negligible.
Step 4: Analyze statement (b): 'In reactions that we draw with a single-headed arrow, the equilibrium constant has a value that is very close to zero.' For reactions that go to completion, the equilibrium constant is actually very large, not close to zero, because the concentration of products is much higher than that of reactants at equilibrium.
Step 5: Conclude that statement (b) is false because a large equilibrium constant indicates a reaction that favors the formation of products, not a value close to zero.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Equilibrium Constant

The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a reversible chemical reaction. It is always a positive value because it is derived from concentrations, which cannot be negative. A K value greater than 1 indicates that products are favored, while a value less than 1 indicates that reactants are favored.
Video consigliato:
Percorso guidato
01:14
Equilibrium Constant K

Single-Headed Arrow in Reactions

A single-headed arrow in a chemical equation indicates a one-way reaction, meaning that the reactants convert to products without reverting back. In such cases, the reaction does not reach equilibrium, and thus the concept of an equilibrium constant does not apply. Therefore, the value of K for these reactions is not defined in the same way as for reversible reactions.
Video consigliato:
Percorso guidato
01:11
Single Displacement Reactions

Equilibrium vs. Non-Equilibrium Reactions

Equilibrium reactions are characterized by the ability to reach a state where the rates of the forward and reverse reactions are equal, allowing for the calculation of an equilibrium constant. In contrast, non-equilibrium reactions, indicated by a single-headed arrow, do not reach this state, and thus the concept of an equilibrium constant is irrelevant. Understanding this distinction is crucial for interpreting the behavior of chemical reactions.
Video consigliato:
Percorso guidato
02:35
Thermal Equilibrium
Pratica correlata
Domanda del libro di testo

Write the expressions for 𝐾𝑐 for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.

(b) Ti(𝑠) + 2Cl2(𝑔) ⇌ TiCl4(𝑙)

460
views
Domanda del libro di testo

Which of the following statements are true and which are false? (c) As the value of the equilibrium constant increases, the speed at which a reaction reaches equilibrium must increase.

1011
views
Domanda del libro di testo

If 𝐾𝑐 = 0.042 for PCl3(𝑔) + Cl2(𝑔) ⇌ PCl5(𝑔) at 500 K, what is the value of 𝐾𝑝 for this reaction at this temperature?

1203
views
Domanda del libro di testo

Which of the following reactions lies to the right, favoring the formation of products, and which lies to the left, favoring the formation of reactants?

(a) 2 NO(g) + O2(g) ⇌ 2 NO2(g) Kp = 5.0 × 1012

(b) 2 HBr(g) ⇌ H2(g) + Br2(g) Kc = 5.8×10−18

574
views