Can't answer this chem Q ><' (1 Viewer)

[Ryuu-jin-jakka]

This is from the 2001 HSC Chemistry i'm having a real hard time answering this Q
Q18. C. (3 marks)
A student removes the voltmeter from the circuit and replaces it with an
electrical generator. The generator causes the copper electrode to increase in
mass
Explain, using an equation, why the copper electrode will increase in mass

(i've never studied what happen to the mass of the electrode little lone any other electricity circuit. and need help on this question) and one more thing, which dot-point does it go under??? seriously you are meant to be test on the dot-point!

 

[Darnie]

This is from the 2001 HSC Chemistry i'm having a real hard time answering this Q
Q18. C. (3 marks)
A student removes the voltmeter from the circuit and replaces it with an
electrical generator. The generator causes the copper electrode to increase in
mass
Explain, using an equation, why the copper electrode will increase in mass

(i've never studied what happen to the mass of the electrode little lone any other electricity circuit. and need help on this question) and one more thing, which dot-point does it go under??? seriously you are meant to be test on the dot-point!

some sort of complete question is needed; what is the full question? a link or something, or the complete question is needed.
From what circuit are we removing the voltmeter from?

 

[Ryuu-jin-jakka]

Oh soot, sorry, yeah i don't think they are related Qa) is asking you to draw a salt bridge and b) is find the standard potential which is 1.14V

 

[FLYHAWK14]

This is from the 2001 HSC Chemistry i'm having a real hard time answering this Q
Q18. C. (3 marks)
A student removes the voltmeter from the circuit and replaces it with an
electrical generator. The generator causes the copper electrode to increase in
mass
Explain, using an equation, why the copper electrode will increase in mass

(i've never studied what happen to the mass of the electrode little lone any other electricity circuit. and need help on this question) and one more thing, which dot-point does it go under??? seriously you are meant to be test on the dot-point!

Hey, even after one year I still remember how to answer that HSC question, guess the HSC never completely leaves your memory. Well, from what I remember I think the electrical generator sends electrons into the anode which is undergoing oxidation allowing the copper ions to gain electrons and create copper metal as represented by:

Cu<SUP>2+ </SUP><SUB>(aq)</SUB> + 2e<SUP>-</SUP><SUB>(aq)</SUB>®Cu<SUB>(s)</SUB>

 

[Ryuu-jin-jakka]

okey thx for the answer, and so which dot-point does it go under for this question???

 

[Michaelmoo]

some sort of complete question is needed; what is the full question? a link or something, or the complete question is needed.
From what circuit are we removing the voltmeter from?

Erm. I think it is related to the first two questions. Here is my answer:

In this galvanic half cell, Coppers greater tendancy to ionise means that electrons are transfered from the copper half cell to the silver half cell; thus ionising (and decreasing in mass) the copper electrode. However, the genereator has the ability to reverse the flow of electrons, such that they are now flowing to the copper half-cell. The reaction is reversed, copper ions in solution are now reduced and accumulate on the copper electrode by the equation:

Cu2+(aq) + 2e- -------> Cu(s)

Thus increasing the electrodes mass.

A wierd question for chemistry. Had I not done physics, I would've had no idea what the generator would do, we've never actually done it in chemistry (yet). You had to have realised a generator works in the complete opposite of a battery, that is reversing the reaction.

 

[Ryuu-jin-jakka]

Cool, i;ve just started M&G so i wouldn't know it until the end of the term, thx and i never knew about it being opposite