Quantitative Analysis for Rust (1 Viewer)

[Captain pi]

Dearest chemists:

Is there a way to perform a quantitative analysis to compare corrosion (rates)?

Thank you.

the pi.

 

[rama_v]

Its very difficult though without really sensitive equipment. Since I go to a public school, that was out of the question for our class lol

 

[gershy]

Yes, in a way. You can weigh the pieces of iron before the experiment, then try all the different conditions for the same amount of time. Then when it's over, you can clean the rust of the bits of iron and re-weigh them. The more mass it has lost, the faster the corrosion has been.

 

[Captain pi]

May I presume, therefore, that a qualitative test is sufficient for the HSC?

 

[Haku]

Yes, in a way. You can weigh the pieces of iron before the experiment, then try all the different conditions for the same amount of time. Then when it's over, you can clean the rust of the bits of iron and re-weigh them. The more mass it has lost, the faster the corrosion has been.

you can't. cause Fe and Zn when corroded is soluable in solution. Zn2+ and Fe2+

 

[Necros87]

*hint* NEVER call it rust, specially if your talking zink, call it a 'redish brown deposit' unless asked something about rust, and its still safer to call it corrosion
and about theon only way to quantitatly mesure rust that were ment to know, is the weigh, leave corrode, rub corrosion off, re-weigh

 

[Sirius Black]

*hint* NEVER call it rust, specially if your talking zink, call it a 'redish brown deposit' unless asked something about rust, and its still safer to call it corrosion
and about theon only way to quantitatly mesure rust that were ment to know, is the weigh, leave corrode, rub corrosion off, re-weigh

In this case, the missing mass is the rust?

our teacher actually made the water evaporised and then reweighed.

btw, in this option, are we supposed to know the quantitative analysis for rust
??

 

[Haku]

thats when u take the metal out of the solution u are suppose to clean it and dry it. than weigh it. That give u mass loss. cause just by evaporating the water other ions could be left in there and also Fe and Zn ions are soluble in solution.

 

[serge]

*hint* NEVER call it rust, specially if your talking zink,

*hint* never call it zink

 

[Haku]

lol

10 char

 

[Abtari]

that is the quantitaive measurement of rate of corrosion...

the rate at which the mass decreases...

it can be measured

 

[Haku]

i know. never said it wasn;t though...

well kinda did. well u can do quantative measurement.

 

[serge]

that is the quantitaive measurement of rate of corrosion...

the rate at which the mass decreases...

it can be measured

yeh, its in one of the past papers, except its not in shipwrecks
and its more about a quantitative analysis of a displaced metal

(if the method they use for that question is valid, then the rust
method should be valid aswell)

 

[Haku]

i think they have a question on the experiment you do on different rates of corrosion every year for shipwrecks

 

[serge]

i think they have a question on the experiment you do on different rates of corrosion every year for shipwrecks

could be, but generally you can just 'see' more rust on it
I dont think you have to scrape it off to be correct

 

[Haku]

but thats only qualitative.

but the question don;t ask u either way. so i guess qualitative is fine and save ink.

 

[serge]

but thats only qualitative.

but the question don;t ask u either way. so i guess qualitative is fine and save ink.

wait, but seeing more rust on one nail than the other its not accurate
but its still quantitative right?

 

[Haku]

no. thats qualitative.

but the question generally ask u to write out an experiment to test the rate of corrosion for different metals or for alloys or for under different solutions.

so by saying that u saw more rust on the iron nail is enough to justify that iron is the most likely to corrode.

 

[serge]

no. thats qualitative.

but the question generally ask u to write out an experiment to test the rate of corrosion for different metals or for alloys or for under different solutions.

so by saying that u saw more rust on the iron nail is enough to justify that iron is the most likely to corrode.

I wouldnt call it qualitative, cause qualitative is a statement like
"rust is present on all 3 nails"... but you're right, until you weigh
the amount my method isn't quantitative either

 

[Necros87]

and as i said b4, never describe it as rust, in an experiment you are ment to have observations, not assumptions, you need to think as a two y/o and say what it looks like, ie 'brown shit on a nail' but in a more exam friendly way