Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. Neuron cells generate electrical signals by concentration gradients across me

ID: 694709 • Letter: 1

Question

1. Neuron cells generate electrical signals by concentration gradients across membranes. Assuming a potassium ion concentration of 0.00300 M inside the cell, and a concentration of 0.135 M outside the cell, what is the electrical potential across the cell membrane? Body temperature is 310 K. The sign identifies the change in the electrical potential across the membrane and which way the ions flow. I. The oxidation of methanol, as described by the equation below, has a Go value of-9379 kJ/mol. What is the standard cell potential for a methanol fuel cell? 2 CH,0H( 1 ) + 3 O2(g) 2 CO2(g)+ 3 H2O( 1 )

Explanation / Answer

1.

Ecell = Eocell - RT/nFln[reduction]/[oxidation]

oxidation = K ------>K+ + e-

reduction = K+ + e ----->K

Eocell = 0 as both oxidation and reduction occuring for same species

n = no. of electron transfer = 1 in this case

F = faraday's constant = 96500C

R = gas constant = 8.314 J/mol.K

T = temperature = 310K

Ecell = -8.314J/mol.K x 310K / 1 x 96500 ln[0.00300]/[0.135]

= 0.1017 V

2.

G = -nFEocell

n = change in oxidation no. = no. of electron transfer

In CH3OH ,oxidation no. of C = -2
in CO2 = +4

no. of electron transfer = 6

-937.9 kJ/mol = -937900 J/mol = -6 x 96500C x Eocell

Eocell = 1.62 V