# chemistry

Calculate the Gibbs free energy change for the reaction below when initial concentrations of CR3+ and Cu2+ are 1 M (F= 96500 J/V mole e-)
2Cr3+ (aq) + 3Cu (s) --> 2Cr (s) + 3Cu2+ (aq)

I assume we use the deltaG= -nFE equation, but how do you know n when Cr is using 3 e- and Cu is using 2 e-. and how do you find E? which is the cathode/anode?

1. 👍 0
2. 👎 0
3. 👁 400
1. The value for n depends upon how you solve the problem. If you use the total balanced equation as you have it written, then n is the total number of electrons (6 in this case) exchanged. If you decide to solve it by calculating the half cell potential for EACH, then adding the two half cells to obtain the total reaction (in which case you DON'T multiply Cu E by 3 and Cr E by 2) then n is 2e for the copper half and 3e for the Cr half. As for the anode/cathode part,
if you work using the entire equation, if E is +, then Cr will be the anode (anode is where oxidation occurs and Cr is losing electrons which makes it oxidized) but if E is -, the Cu will be the anode and Cr the cathode.

1. 👍 0
2. 👎 0
posted by DrBob222
2. 623

1. 👍 0
2. 👎 0

## Similar Questions

1. ### biochemistry

when a reaction AB starts, there is three times as much product as reactant. When it reaches equilibrium, there is twice as much product as reactant. Show how to calculate the standard change in gibbs free energy for this

asked by Jennifer on November 20, 2009
2. ### CHEMISTRY - BATTERIES

What is the voltage and the Gibbs Free Energy for the following reaction? (Assume standard conditions) 3Sn^2+ (aq) + 2Al (s) --> 2 Al^3+ (aq) + 3 Sn (s) Now calculate the Gibbs Free Energy for the above reaction if Sn^2+ (aq) is

asked by DAN on November 9, 2015
3. ### Chemistry

A reaction: A(aq)+B(aq)C(aq) has a standard free-energy change of –4.69 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40 M,

asked by Robin on November 6, 2014
4. ### chemistry

Under standard conditions, the Gibbs free energy of the reactants G,std(reactants) in a reaction in the gas phase is 232.94 kJ and the Gibbs free energy of the products G,std(products) is 211.56 kJ. Calculate the value of the

asked by bekah on April 28, 2014
5. ### Chemistry

Under standard conditions, the Gibbs free energy of the reactants G,std(reactants) in a redox reaction in aqueous solution is 360.65 kJ and the Gibbs free energy of the products G,std(products) is 158.14 kJ. The number of moles,

asked by Daphne on March 16, 2016
6. ### Chemistry

A reaction: A(aq) + B(aq) C(aq) has a standard free-energy change of –4.65 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40

asked by Katherine on November 24, 2013
7. ### Chemistry

A reaction A+B---> C has a standard free energy change of -5.13 kj/mol at 25 degrees celcius, What are the concentrations of A, B, and C at equilibrium if at the beginning of the reaction there concentrations are .3M, .4M, and 0M

asked by juan777 on September 6, 2011
8. ### Chemistry

A reaction : A(aq)+B(aq) --> C(aq) has a standard free-energy change of –4.01 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M,

asked by Alex on April 28, 2014
9. ### Chemistry

A reaction has a standard free-energy change of –4.60 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40 M, and 0 M,

asked by MyHumPs on April 25, 2014
10. ### Chemistry

A reaction A(aq)+B(aq)C(aq) has a standard free-energy change of –3.35 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40 M,

asked by ACDub on March 30, 2014

More Similar Questions