1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
pishuonlain [190]
3 years ago
14

Please answer this question ASAP. This is on a homework assignment that is due tonight!! Thank you in advance! A voltaic cell em

ploys the following redox reaction: 2Fe3+(aq)+3Mg(s)→2Fe(s)+3Mg2+(aq) Calculate the cell potential at 25 ∘C under each of the following conditions.
a. find Ecell at standard conditions
b. when [Fe3+]= 1.0×10−3 M ; [Mg2+]= 2.90 M find Ecell
c. when [Fe3+]=2.90M; [Mg2+]=1.0*10^-3 M find E cell
Chemistry
2 answers:
worty [1.4K]3 years ago
7 0
Ecell = E°cell - RT/vF * lnQ

R is the gas constant: 8.3145 J/Kmol
T is the temperature in kelvin: 273.15K = 0°C, 25°C = 298.15K
v is the amount of electrons, which in your example seems to be six (I'm not totally sure)
F is the Faradays constant: 96485 J/Vmol (not sure about the mol)
Q is the concentration of products divided by the concentration of reactants, in which we ignore pure solids and liquids: [Mg2+]³ / [Fe3+]²

Standard conditions is 1 mol, at 298.15K and 1 atm

To find E°cell, you have to look up the reduction potensials of Fe3+ and Mg2+, and solve like this:

E°cell = cathode - anode

Cathode is where the reduction happens, so that would be the element that recieves electrons. Anode is where the oxidation happens, so that would be the element that donates electrons. In your example Fe3+ recieves electrons, and should be considered as cathode in the equation above. 

When you have found E°cell, you can just solve with the numbers I gave you. 
White raven [17]3 years ago
3 0

a. E° cell = 3.14 V

b. E cell = 3.11 V

c. E cell = 3.16 V

<h3>Further explanation </h3>

Cell potential (E °) is the potential difference between the two electrodes in an electrochemical cell.

Electric current moves from a high potential pole to a low potential, so the cell potential is the difference between an electrode that has a high electrode potential (cathode) and an electrode that has a low electrode potential (anode)

\large {\boxed {\bold {E ^ osel = E ^ ocatode -E ^ oanode}}}

or:

<h3>E ° cell = E ° reduction-E ° oxidation </h3>

(At the cathode the reduction reaction occurs, the anode oxidation reaction occurs)

The value of E cells uses a reference electrode which is used as a comparison called the Standard Electrode which is the hydrogen-platinum electrode

The potential cell for nonstandard conditions we can use the Nernst equation

\rm E = E ^ o -\dfrac {RT} {nF} lnQ

For standard temperature T = 298 K,

\rm E = E ^ o- \dfrac {0.0592V} {n} log \: Q

Q = the reaction quotient

In reaction:

2Fe³⁺ (aq) + 3Mg (s) → 2Fe (s) + 3Mg²⁺ (aq)

Given:

Mg²⁺ + 2e⁻ → Mg (s) = –2.37V and

Fe³⁺ + 3e⁻ → Fe (s) = 0.77V

From the value of E cells, it can be seen that the higher E cells will act as cathodes namely Fe³⁺

So the reaction happens

at the anode (oxidation reaction) Mg (s) ------> Mg²⁺ + 2e⁻ E ° = + 2.37V

at the cathode (reduction reaction) Fe³⁺ + 3e− → Fe (s) = 0.77 V

E ° cell = E ° cathode -E ° anode = 0.77 V - (-2.37V) = 3.14V

Mg (s) ------> Mg²⁺ + 2e⁻ E ° = + 2.37V x 3

Fe²⁺ + 3e− → Fe (s) E ° = 0.77 V            x2

============================= +

2Fe³⁺ (aq) + 3Mg (s) → 2Fe (s) + 3Mg²⁺ (aq) E ° cell = 3.14V

From Nerst equation

n = 6 (6 electron transfer)

b. when [Fe³⁺] = 1.0 × 10⁻³ M; [Mg²⁺] = 2.90 M

\rm Q = \dfrac {2.9} {1.0.10^{-3}} = 2900

\rm E = E ^ o- \dfrac {0.0592V} {n} log \: Q \\\\ E = 3.14- \dfrac {0.0592} {6} log2900 \\\\ E = 3.11 \: V

c. when [Fe³⁺] = 2.90M; [Mg²⁺] = 1.0 * 10⁻³ M

\rm Q = \dfrac {1.0.10^{-3}} {2.9} = 3.44.10^{-4}

\rm E = E ^ o- \dfrac {0.0592V} {n} log \: Q \\\\ E = 3.14- \dfrac {0.0592} {6} log3.44.10^{-4} \\\\ E = 3.16 \: V

<h3>Learn more </h3>

The standard cell potential

brainly.com/question/9784301

brainly.com/question/1313684

Nerst equation

brainly.com/question/11638563

You might be interested in
Between HClO3 and HIO3, which is stronger and why? Question 16 options: 1) HClO3 is stronger because chlorine is in a higher oxi
natima [27]

Answer:

2) HClO3 is stronger because chlorine is more electronegative than iodine.

Explanation:

The more electronegative the element is the more strong or acidic it becomes.

Chlorine being more electronegative than Iodine makes it easier for it to pull the electron of hydrogen more strongly and hence has a higher tendency to release a H+ unit. Hence that makes it stronger.

4 0
3 years ago
Help me plss ty in advanced​
Komok [63]

Answer:

See below ~

Explanation:

The respective pairs are :

× Ribose ⇒ The sugar of RNA

× Double helix ⇒ Structures of DNA

× Watson & Crick ⇒ Proposed the double helix model

× Base pair ⇒ Adenine - Thymine pair

× Cytosine ⇒ The nucleotide pair of Guanine

3 0
2 years ago
Which property is typical of an acid ?
LenaWriter [7]
Properties of acids are turns blue litmus red. pH is below 7 , reacts with metals to give off hydrogen gas and they have a sour taste. So option B will be the answer. 
6 0
3 years ago
2. The ions in an ionic compound separate from each other when
kkurt [141]

Answer:

A. when dissolved in water

Explanation:

Water is an extremely polar molecule, meaning it has a positive end a negative end. When an ionic compound is dissolved, the positive pole of water will be attracted to the negative ion and attach itself to it. The same goes for the positive ions. That's how water breaks down ionic compounds

7 0
3 years ago
Read 2 more answers
If you rewrite the following word equation as a balanced chemical equation, what will the coefficient and symbol for fluorine be
IgorLugansk [536]

Answer:

2NF3------->N2 +3F2

Explanation:

For the equation to be balanced, there must be six fluorine atoms on both left and right hand sides of the chemical reaction equation. Hence the coefficient of chlorine on the right hand side must be three for the equation to be balanced.

6 0
3 years ago
Read 2 more answers
Other questions:
  • How is the rate of appearance of h2o related to the rate of disappearance of o2?
    7·1 answer
  • Which example provides a complete scientific description of an object in motion? Question 3 options: The marble changed position
    15·2 answers
  • What salt is produced in each of the following neutralization reactions?
    15·2 answers
  • Why is aluminum a substance
    11·2 answers
  • A solute is a strong electrolyte that ionizes into 2 ions. What is the molar mass of this solute if 30.76 grams added to exactly
    9·1 answer
  • How do the chemical characteristics of carbon affect the characteristics of organic molecules?
    5·1 answer
  • A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.000kg of wat
    7·1 answer
  • A device that transforms chemical energy to electrical energy, and provides electrical force in a current.
    9·1 answer
  • Which sources are reliable? Check all that apply.
    9·2 answers
  • Consider the half reaction below.
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!