alternative renewable sources

[physics]

Is it okay for nuclear fusion and fission to say that they don't create pollution or do i have to say fewer/less pollution.

and is it okay to say that nuclear fusion is better because it has a higher energy density than fossil fuels?
i was just unsure if they would accept it on vcaa answers.

[masonnnn]

they result in nuclear fuel rods etc that have to be stored and don't decay for thousands of years... so it does make pollution, direct pollution to the air is definitely less though but i think the better reason is the better energy conversion/ less wasted energy

[kyzoo]

0.o Nuclear fission and fusion definitely have higher energy density than fossil fuels. I remember reading in the textbook that 1kg of uranium releases the same energy as 2500 tonnes of coal, and that 1kg of fusion fuel releases the same energy as 10000 tonnes of coal.

And as for pollution, just specify what type of pollution: i.e. - no atmospheric pollution

[Martoman]

make sure you realise FUSION is impossible atm!

[physics]

yeh thanks.
and what r the advantages of fossil fuel ? i only know that it is convinient ad provides high energy yeilds? i dont even think that is right?

AND does the polarity change when something is recharging and since u have to flip the eqaution over does that mean instead of undrgoing oxidation they r reducing and instead of the negative anode it becomes the positive cathode?
basically what changes? i'm really lost?

[Martoman]

advantages is that atm there are:

-quite a lot of it still around
-its very convienient as all the infrastructure is in place.
-there is a constant supply going into the plants not like biofuels where you need to till fields, chop it up mince it and so forth.
- acceptable levels of energy yeilds but this will not be the case going into the future as demand increases exponentially as population increases.

Thats about all i can think of atm.

For the battery stuff I just remember discharging is galvanic cell. So.

Anode (-)
Cathode(+)

For recharging just swap the words keep the charges where they are.

Cathode(-)
Anode(+)

Its exactly the same thing as an electrolysis cell.

[physics]

are u sure ? =D not that i dun trust u its just that is there a reasoning. is it because the equatiosnof the half equatiosn r swapped around so the processes are different but its still negative and postive either way?

[Martoman]

yes im sure.

The logic is the same for electrolyctic cells.

You want to force oxidation at the anode. To do that you need to somehow suck the electrons out of the species there. Because electrons are negative, you can apply the positive terminal to do so... it acts as a vaccuum cleaner of sorts.

Similarly, you want to FORCE reduction to occur at the cathode so you bombard that with electrons from the -ve terminal. This will force the species there to accept electrons.

[physics]

So when u recharge do u have to change the +ve wiring to the negative one and vice versa?
apparently in VCAA...even when u recharge the +ve is with the +ve and -ve with -ve?
is that right?

[Martoman]

lol you don't have any battery wiring when discharging coz its a galvanic cell.... but now you've got me confused here as to the real world application of this... 

[physics]

oh sorry the question is basically during recharge is the battery + to + and - to -...

[physics]

advantages is that atm there are:

-quite a lot of it still around
-its very convienient as all the infrastructure is in place.
-there is a constant supply going into the plants not like biofuels where you need to till fields, chop it up mince it and so forth.
- acceptable levels of energy yeilds but this will not be the case going into the future as demand increases exponentially as population increases.

Thats about all i can think of atm.

For the battery stuff I just remember discharging is galvanic cell. So.

Anode (-)
Cathode(+)

For recharging just swap the words keep the charges where they are.

Cathode(-)
Anode(+)

Its exactly the same thing as an electrolysis cell.

DUDE! i read my textbook AND I GET IT! =D
so basically
if discharging is
+ -reduction cathode
-   oxidation anode

when it is recharging
+ anode oxidation
- cathode reduction


JUST LIKE ELECTROLYSIS! JUST LIKE U SAID...just took me a while to get it =D

wait am i thinking it right?

[Martoman]

yepsies