Calculate the Gibbs free energy change (ΔG) for a cell with E° = 0.75 V and n =
Practice Questions
Q1
Calculate the Gibbs free energy change (ΔG) for a cell with E° = 0.75 V and n = 2 moles of electrons transferred.
-150 kJ
-75 kJ
75 kJ
150 kJ
Questions & Step-by-Step Solutions
Calculate the Gibbs free energy change (ΔG) for a cell with E° = 0.75 V and n = 2 moles of electrons transferred.
Step 1: Identify the formula for Gibbs free energy change (ΔG), which is ΔG = -nFE°.
Step 2: Determine the values needed for the calculation: n (number of moles of electrons) is 2, F (Faraday's constant) is 96485 C/mol, and E° (standard cell potential) is 0.75 V.
Step 3: Substitute the values into the formula: ΔG = -2 * 96485 C/mol * 0.75 V.
Step 4: Calculate the product of 2, 96485, and 0.75: 2 * 96485 = 192970, then 192970 * 0.75 = 144727.5.
Step 5: Apply the negative sign to the result: ΔG = -144727.5 J.
Step 6: Convert the result from joules to kilojoules by dividing by 1000: -144727.5 J / 1000 = -144.73 kJ.
Gibbs Free Energy – The Gibbs free energy change (ΔG) indicates the spontaneity of a reaction, calculated using the equation ΔG = -nFE°.
Electrochemistry – Understanding the relationship between cell potential (E°), number of electrons transferred (n), and Gibbs free energy.
Units of Measurement – Recognizing the units involved in the calculation, such as volts (V), coulombs (C), and kilojoules (kJ).
