help on prac (1 Viewer)

[jm1234567890]

i made a battery using zinc, copper, electrolytes and a porous container.

the prac was to heat it up and see if the voltage over the electrodes would increase

it did not, in fact it decreased from 1.05v to 1.03v when the temp went to 50degrees

i think it is because temperature increases the resistance in the metal, what do you think?

please help...

 

[McLake]

Did you repeat to check for errors?

Assuming you are doing everything else right I would have to agree that it must be the metals resistance increasing that is decreasing the current, since temprature should increse the rate of reaction.

 

[spice girl]

resistance shouldn't affect voltage, it really only affects current.

are you sure that it's supposed to increase? If the zinc-copper cell is exothermic, we should expect it to decrease because of le-chatelier's principle.

but idunno whether it's exothermic or endothermic.

and it could also be instrumental error. Are you using a nice-digital or a cheapo-analog voltmeter?

 

[Lord Ac]

Well, can anyone answer me why my Iodinde didnt change color in cyclohEXane??

Ac

 

[McLake]

Originally posted by Lord Ac
Well, can anyone answer me why my Iodinde didnt change color in cyclohEXane??
Ac

Should it? What principle are you using?

 

[spice girl]

Originally posted by Lord Ac
Well, can anyone answer me why my Iodinde didnt change color in cyclohEXane??

Ac

because cyclohexane doesn't have any double-bonds

 

[McLake]

Originally posted by spice girl

because cyclohexane doesn't have any double-bonds

It's that the "Bromine water" exmeriment? Or does Iodine work in the same way since its part of the same group?

 

[Lord Ac]

Soree folks, what I meant was HexENE (WITH THE C=C bond!!). I did it AGAIN today and it still didnt work. THEN, I made up my OWN IODINE shit with the teacher and still nothing...

Im pretty sure the yellow iodine should dissaear like trhe bromine ...

Ac

 

[spice girl]

i've had a look at some "literature", it said that Iodine generally fails to react with the dblbond. Perhaps the I- ion is less stable than the Br- or Cl- ion?

 

[Lord Ac]

Well, dont ask me ... or my teacher. You know how good he is ... (ie. not!)



Ac