Why is it important that the polymer membrane in a pem fuel cell allows only protons to move through it?
it forces the electrons to move through an external circuit, where they can do work.
it prevents the protons from reacting with the compounds in the rest of the fuel cell.
it allows the protons to build up potential energy and release more energy when they react with oxygen.
it keeps the electrons from corroding the interior of the pem fuel cell.

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

Δu of , in kj/kg, as it isto k, (a)as a of , (b) at , (c) at .

8. what happens to matter during a chemical reaction