chemistry

Hey...how r u guys..thanks for helping me on my previous questions...can u help me solve two questions and check one? Thanks, all the questions are related to the info given:

In some industrial processes, sodium chromate is added to water coolants.
When the coolant is drained, the chromate ions can be removed through an
electrolysis process that uses an iron anode. The products of the electrolysis
are aqueous iron(II) ions and solid chromium(III) hydroxide, a recoverable
pollutant. The half-reaction involving the chromate ion is

CrO42–(aq) + 4 H2O (l) + 3 e –>>>Cr(OH)3(s) + 5 OH –(aq)


21. a) Provide the half-reactions and a net redox reaction for this electrochemical
process.

b) A current of 3.00 A is applied for 48.0 h to a cell containing a 400 g iron
anode. What is the final mass of the iron anode?
My answer:
The final mass of iron anode is 700grams.


c) Suggest an alternative anode material that would last longer than iron. Support
your answer with relevant calculations and explanations.


How can the final mass of iron be greater than the initial mass? It seems to me that you are an answer moocher, fishing for answers. Do you ever show your work?


ummm...that is my answer and I just want to know how to do this. I am not that great at chem, but want to understand the questions I do. If u hate it, fine! I just want to know how to do this.


Hey, sorry anonymous, I am just real frustrated from chem cause I don't get it and I have my final on Tuesday. I shouldnt have got mad, but I did and sorry!


Here are some hints.

In some industrial processes, sodium chromate is added to water coolants.
When the coolant is drained, the chromate ions can be removed through an
electrolysis process that uses an iron anode. The products of the electrolysis
are aqueous iron(II) ions and solid chromium(III) hydroxide, a recoverable
pollutant. The half-reaction involving the chromate ion is

CrO42–(aq) + 4 H2O (l) + 3 e –>>>Cr(OH)3(s) + 5 OH –(aq)


21. a) Provide the half-reactions and a net redox reaction for this electrochemical
process.
The problem gives one half reaction in the CrO4^2- going to Cr(OH)3(s). The second half reaction is given in the preamble as the iron electrode going into solution as the ferrous ion; therefore, that half reaction is Fe(s) ==> Fe^2+(aq) + 2e
Now you want to add these two equations together. To do this, however, you must first make the electrons lost in the first reaction (3e) and the electrons gained in the iron reaction (2e) equal. You do that by multiplying the iron half reaction by 3 and the chromate half reaction by 2 (that makes six electrons lost and six electrons gained). Then add those two equations (the ones you obtain from multiplying) together.

b) A current of 3.00 A is applied for 48.0 h to a cell containing a 400 g iron
anode. What is the final mass of the iron anode?
My answer:
The final mass of iron anode is 700grams.
Show us what you did on this. We need you to show your work in order to understand where you may have gone wrong. For example, the preample tells us that the iron electrode is going into solution as ferrous ion (that is Fe^+2). Therefore, I would expect the final mass of the iron electrode to be less than 400 grams.

c) Suggest an alternative anode material that would last longer than iron. Support
your answer with relevant calculations and explanations.
I would look for an element that takes more coulombs to convert from metal to ions. That means look for a metal that has a half reaction involving more than 2 electrons. The activity series might be the place to start.I hope this helps. Please post any follow up questions just one question per post. It is more convenient to handle that way and show any work you have done. Finally, tell us exactly what you don't understand.

  1. 👍 0
  2. 👎 0
  3. 👁 190
asked by David

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    hey i have a some questions i am trying to solve for practice, because i have a test coming up. can you guys help me with them? i will post them Yes. Please show your work, however. Physics is best learned through practice, not by

    asked by gomez on August 7, 2007

  2. Rates

    Guys, how much would you rate this website? From 1-10. Do you feel like others are helping you with your questions? Remember that we don't solve for you. We explain the situation you are in and then you solve it on your own. This

    asked by Light Bulb on January 21, 2017

  3. chemistry

    Hey, I was just wondering if anyone has previous chma11 term tests, or has sample questions or anything to help study for the test..if so can u post the questions here..or lets figure something. thnx

    asked by 123QWE on June 4, 2009

  4. general

    I really don't like the fact that you guys are skipping so many questions we need help here and were not getting it. i understand that no one knows everything but, please don't skip the questions its really hard when i need help

    asked by Anonymous on March 28, 2012

  5. Math

    (8x-5)/(12x+3) = 5/9 Hey guys, could someone please solve for x? I'm not sure how to simplify this equation -\_(ツ)_/- Many thanks.

    asked by Azuka on November 8, 2018

  6. History (Unit 2 History exam Unit 2 Lesson 10)

    Hey guys! I need help in my History unit 2 exam for 8th grade, I was wondering if any of you took it yet and could help me with some of the questions... I really need help it's very hard! >.< Can u pretty please help? T-T

    asked by Kiki on November 4, 2015

  7. physics

    hey you guys , i reay appreciate it if you guys help me out . Q: a vector is a physica quantity that has which of the following properties ( can be more than one) a)magnitude b)color c)speed d)direction

    asked by kevin on April 12, 2012

  8. English

    Hey guys, I was just wondering if you could help me find or explain to me media influence in the Hunger Games. I know this is a big part of the story, but I really need clarification. Thanks a lot guys!

    asked by Alex on January 13, 2011

  9. maths

    guys need help on ODE questions, i just need you guys to tell me what method to use for the following equations and i will try solve them myself: a) (2y+tany)dx +(x-x^2(tany))dy=0 b) y'=(e^x)(2y+(e^x))+y(1+y) c) y'=1+y^2-x^2 any

    asked by lim on September 24, 2016

  10. Goodbye, Ms.Sue =(

    I am so broken. This is everyone's fault (not the tutors). You guys told Ms. Sue to kill herself, and worst. you guys should feel ashamed. She tried helping you guys but you were bullying her. I'm so happy that Ms. Sue is in a

    asked by HomeworkStan on December 10, 2019

  11. Thank you Jiskha Teachers

    I just wanted to say thank you jiskha teachers for helping me get through 8th grade. My last day of school was yesterday and I'm going on to highschool next year. Thanks for helping work out, check, or help me solve any problems I

    asked by Jordan on June 2, 2018

More Similar Questions