chemical cells + fuel cells - SC16

Question 1

what are examples of chemical cells?

Answer 1

everyday batteries used in phones + torches

Question 2

what are the components of simple chemical cells

Answer 2

• 2 different metals dipped into a solution of one of their salts
• a ‘salt bridge’ to allow dissolved ions to pass between

Question 3

What are the main differences betweem chemical cells and fuel cells?

Answer 3

chemical : store all their reactants - produces a voltage until one of the reactants is all used up

fuel: are supplied with fuel + oxygen from outside - no burning takes place and they produce a voltage for as long as reactants are supplied

Question 4

what is the only product of fuel cells?

Answer 4

water

Question 5

what are the benefits / drawbacks of fuel cells?

Answer 5

benefits :
* a hydrogen-oxygen fuel cells + electric motor are much quieter and need less maintenance than petrol/disel engine
* hydrogen-oxygen fuel cells dont produce carbon dioxibe (greenhouse gas)
* only require hydrogen + oxygen
* last longer

drawbacks:
* some process of producing this fuel cell releases co2 as by-producr
* Needs ore space to be stored
* hydrogen is a gas
* Explosive when exposed with air
* Requires energy

Question 6

in terms of re-dox reactions, what happens in the fuel cell?

give complete equation too

Answer 6

oxidation of hydrogen and reduction of oxygen - 2H2 + O2 -> 2H2O

Question 7

give the half-equation of the reaction taking place at one of the electrodes in a hydrogen-oxygen fuel cell?

(gains electrons)

Answer 7

O(2) + 4H(+) + 4e(-) -> 2H(2)O