Chemistry: Electro chemistry help PLEASE?

[ally.hady]

Chemistry: Electro chemistry help! PLEASE?

Photographic film contains a thin layer of silver bromide (AgBr) Crystals. When the light hits the film. Electrons are transferred from the Br- to the Ag + ions. Dark patches of metallic silver appear on the film where the lens of the camera focused light on the film.

a) why is this considered a redox reaction?
b) write the oxidation half reaction.
C) what substance is the anode
d) write the reduction half reaction
e) what substance is the reducing agent
f) what would be the e* of the tiny cell on the photo graphic film
g)is this cell electrochemical or electro lytic

please help me final exam tomorrow and i don't understand this unit... just give me hints or if u can show me how i would do it... steps would help too thankyou in advance!

 

[Borek]

If you have final tomorrow it is already too late, besides, your post is against forum rules. But let's try to give you at least some basic information.

By definition, every reaction where charge is transferred between atoms and/or molecules, is called a redox reaction. To find out what is getting oxidized and is what getting reduced you can use OIL RIG - oxidation is lose, reduction is gain (of electrons). Reducing agent is the one that reduces something else (it means it gets oxidized in the process).