Textbook Question
At 298 K a cell reaction has a standard cell potential of +0.17 V. The equilibrium constant for the reaction is 5.5 × 105. What is the value of n for the reaction?
Ch.20 - Electrochemistry
Chapter 20, Problem 66
A voltaic cell is constructed with all reactants and products in their standard states. Will the concentration of the reactants increase, decrease, or remain the same as the cell operates?
Verified step by step guidance1
Step 1: Understand that a voltaic cell, also known as a galvanic cell, is an electrochemical cell that generates electrical energy from spontaneous redox reactions occurring within the cell.
Step 2: Recall that in a voltaic cell, the anode is where oxidation occurs, and the cathode is where reduction takes place. Electrons flow from the anode to the cathode through an external circuit.
Step 3: Recognize that as the cell operates, the reactants are consumed in the redox reactions. At the anode, the substance being oxidized loses electrons, and at the cathode, the substance being reduced gains electrons.
Step 4: Consider the effect of the cell operation on the concentration of reactants. As the cell continues to operate, the reactants are converted into products, leading to a decrease in the concentration of reactants over time.
Step 5: Conclude that since the reactants are being consumed to produce electrical energy, the concentration of the reactants will decrease as the voltaic cell operates.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Voltaic Cell
A voltaic cell, also known as a galvanic cell, is an electrochemical cell that converts chemical energy from spontaneous redox reactions into electrical energy. It consists of two half-cells, each containing an electrode and an electrolyte. The flow of electrons from the anode to the cathode generates an electric current, and the cell operates until the reactants are consumed or reach equilibrium.
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The Electrolytic Cell
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 a voltaic cell, as the cell operates, the reactants are converted into products, which can shift the equilibrium position. Understanding how concentrations change during the reaction is crucial for predicting the behavior of the cell over time.
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04:21Chemical Equilibrium Concepts
Le Chatelier's Principle
Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change and restore a new equilibrium. In the context of a voltaic cell, as reactants are consumed during the reaction, the principle helps predict that the concentration of reactants will decrease, leading to a shift in equilibrium towards the products.
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Related Practice
Textbook Question
A voltaic cell utilizes the following reaction: Al1s2 + 3 Ag+1aq2 ¡ Al3+1aq2 + 3 Ag1s2 What is the effect on the cell emf of each of the following changes? (a) Water is added to the anode half-cell, diluting the solution.
Textbook Question
A voltaic cell is constructed that uses the following reaction and operates at 298 K: Zn(s) + Ni2+(aq) → Zn2+(aq) + Ni(s) (b) What is the emf of this cell when [Ni2+] = 3.00 M and [Zn2+] = 0.100 M? (c) What is the emf of the cell when [Ni2+] = 0.200 M and [Zn2+] = 0.900 M?