Question

iamabear
In the TV show "Breaking Bad" the characters attempt to use HF acid to dissolve guns (among other things). Here we consider instead dissolving guns (which we will assume are pure iron) with sulfuric acid.

Complete the balanced reaction for reacting iron in dilute sulfuric acid to form aqueous FeSO4. Do not worry about formatting subscripts (i.e. O2 to represent diatomic oxygen gas is fine).

Fe + H2SO4 → FeSO4 + __H2(g)___

Answer 1

It is apparent that they must use an outside source of electrical power to drive the dissolution of the iron. They use a small current so that the dissolution proceeds with the minimum voltage required. Assume standard values for the electrochemical potentials.

How much electrical energy supplied this way is thus required to dissolve an additional 1 kg of iron? Give your answer in kJ.

Answer 2

@aaronq

Answer 3

okay, so let's think about it.

The reaction is \(Fe \rightarrow 2 e + Fe^{2+}\) and \(2H^+ + 2e \rightarrow H_2\)

so if we use \(E_{cell}=E^{red}_{red}-E^{oxd}_{red}\), \(E_{Cell}=0-(-0.44)\)

i think we need to use: \(\Delta G=nFE_{cell} \)

\(\Delta G=(2)*(9648.5 C/mol)*(0.44~J/C)=8490.68~J/mol\)

1000g/55.8=17.9 moles of iron

8490.68 J/mol*17.9 moles of iron= 151983.172 J = 152 kJ

it seems like a lot, though

Answer 4

wrong

Answer 5

152 = wrong answer

Answer 6

so where do you think i went wrong?

Answer 7

let me see

Answer 8

where is the 2kg?

Answer 9

@aaronq is that 2kg?

Answer 10

maybe the question is not a good question.

Answer 11

i'm not sure if it's supposed to be 1 kg or 2 kg. It says "to dissolve an additional kg".

Answer 12

you could try multiplying that number by 2

Answer 13

but 152 is wrong....lets try 2x

Answer 14

its 304 and wrong still

Answer 15

your raw answer: 151.983172 is also wrong...lol

Answer 16

151.983172 and 152 and 304 are all wrong answers....i duno man....so hard

Answer 17

do you have any of these types of problems in your notes?

Answer 18

no lol that why im stuck

Answer 19

let me see

Answer 20

is electrical energy this? http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepe.html#c1

Answer 21

the question is under engineering and solar power mechanisms

Answer 22

oh wait, i wrote faradays constant wrong, it's 96,485 C/mol

so: 0.44*2*96485=8490.68 J/mol

8490.68 J/mol*17.9 mol=1519831.72 J = 1520 kJ

Answer 23

doesn't work still

Answer 24

wait let me try raw

Answer 25

let me try without rounded

Answer 26

this is electrochemistry, related, but not the same as the link you posted.

Answer 27

one moment

Answer 28

hm none of teh answer work

Answer 29

@aaronq none of the answer works both rounded and non-rounded, but it only accepts raw numbers un-rounded

Answer 30

@aaronq lets just give up ok?

Answer 31

hmm sure. I don't think i'm making a mistake, but leave it open. Maybe someone will come and take a look and spot where we went wrong.

Answer 32

you are right but i dont think it is in the right format or u might have missed something the question wants you to do

Answer 33

i do not doubt that your answer is wrong but the system didnt accept it.

Answer 34

do you think it's asking for the energy for 2 kg?

Answer 35

we ar just missing something...could be another number factor or somtin i do not know

Answer 36

multiply it by 2?

Answer 37

2279.74758 doesn't work

Answer 38

gives a X wrong

Answer 39

Its weird that they said "an additional 1 kg". "Additional" implies that there is more than just the 1 kg. Let's leave it. Hopefully someone spots the error.

Answer 40

maybe we take a break im tired lol

Answer 41

haha sounds good.