The following cell was found to have a potential of 0.2897 V:SCEIIMg2+(a = 3.32 * 10^-3M)membrane electrode for Mg^2+(a) When the solution of known magnesium activity was replaced with an unknown solution, the potentialwas found to be 0.2041 V. What was the pMg of this unknown solution?(b) Assuming an uncertainty of 60.002 V in the junction potential, what is the range of Mg21 activitieswithin which the true value might be expected?(c) What is the relative error in [Mg^2+] associated with the uncertainty in Ej?

Subject Year Month, 58 Discuss the mechanism by which the potential of a platinum electrode becomes poised by immer- sion into a solution of Fe(II) and Fe(III) in 1 M HCl. Approximately how much charge is required to shift the electrode potential by 100 mV? Why does the potential become uncertain at low concentra- tions of Fe(II) and Fe(III), even if the ratio of their concentrations is held near unity? Does this ex- perimental fact reflect thermodynamic considerations? How well do your answers to these issues apply to the establishment of potential at an ion-selective electrode? Date. فصل دوم مراجع استاد

5) a) Typical Mg²+ concentrations in blood plasma are 2.2mM. If the transmembrane po- tential across the cell membrane is -90mV (negative inside), calculate the equilibrium con- centration of Mg²+ inside the red blood cell at 37°C. b) Consider the difference in electrochemical potential inside vs outside the cell, Aµreleefchem Helece/chem (inside) – Helec/chem(outside). As discussed in class, this difference is written as a chemical and electrical contribution, Afdee/chem = Aflchem + Atelec: For the red blood cell at equilibrium, state whether Atelee/chem; Atchem, and Aftelec are greater than, less than, or equal to zero, and explain your answer.

The potential of electrodes Cu2+ (aq) | Cu(s) is  ϕ1 = 0.337 V , and  Cu2+ (aq), Cu+ (aq) | Pt  is ϕ2 = 0.153 V , respectively. a) Calculate the value of ϕ0 for electrode Cu+(aq) | Cu(s). [Hint: Write half reactions for the above two electrodes, then derive the target electrode.]b) Calculate the equilibrium constant Ka0 for the reaction Cu(s) + Cu2+ (aq) = 2Cu+ (aq) at 298.15K. [Hint: Based on the reaction, design a cell with two electrodes and verify that the two half reactions will give you the target reaction. Then calculate the cell potential.]

The F− concentration of a solution was determined by measurements with a liquidmembrane electrode. The electrode system developed a potential of 0.5021 V when immersed in 25.00 mL of the sample, and 0.4213 V after the addition of 2.00 mL of 5.45 x 10−2 M NaF. Calculate pF for the sample.

At 25C, you conduct a titration of 20.00 mL of a 0.0400 M AgNO3 solution with a 0.050 M NaI solution within the following cell: Saturated Calomel Electrode | Titration solution | Ag(s) for the cell as writted, what is the voltage after the addition of 10.00 mL of the NaI sooution? The reduction potential for the saturated calomel electrode is E=0.241 V. The standard reduction potential for the reaction: Ag++e- ® Ag(s) E0= 0.79993V. The solubility constant of AgI is Ksp=8.3x10-17 Note: the cell potential could be negative since the condditions are non-standard ones. a)0.169 b)0.354 c)0.235 d)2.360 e)0.441

In the cellPt | Fe3+ ( a = 1), Fe2+ (a = 1) || Ag+ (a =1) | Ag The standard emf at 298 K for the half-cell Ag+ | Ag is 0.80 V, and for Pt | Br2 , Br− is 0.771 V. Calculate the equilibrium constant for the cell reaction at 298 K.[3.2] The answer is in the bracket. Thank you!

Calculate the potential of a zinc electrode in a 0.0500 M solution of Zn (NO3) 2 ?

A platinum electrode is immersed into a solution of 10 mol m-3 KNO3 and poised at -1 V. (1) Sketch how the concentration of potassium ions, [K+], change as a function of distance, x, from the electrode surface. (Calculate the extent to which the electrical double layer protrudes from the electrode surface, assuming a water solvent (\epsi r = 78.1) at 25 deg C I