Lecture 13-14

Question 1

many redox reactions in water care catalyzed by what?

Answer 1

micro-organisms

Question 2

what does a large positive pE mean?

Answer 2

oxidizing environments (and compounds attracts electrons to itself)

Question 3

what does a large negative pE means?

Answer 3

reducing environments (compounds gives up electron)

Question 4

in order to have a spontaneous reactions what needs to be the value of triangle G degree, E degree, or K

Answer 4

triangle G degree < 1 (,egative)
E degree >1 (positive)
K >1

Question 5

if Q less then K

Answer 5

reactants are favored

Question 6

if Q>K what does this mean

Answer 6

products are favored

Question 7

if triangle G > 0 what does this mean

Answer 7

non-spontaneous

Question 8

if triangle G=0 what does this mean

Answer 8

at equilibrium

Question 9

why if we pour cu2+ down a lead pipe, nothing happens but if we pour doen pB down a copper pipe we get precipitate?

Answer 9

value of pE. Copper has a large positive, but lead has a large negative.

lead pipe: -2.13-5.71= very negative number and not spontaneous
Copper pipe: 5.71- -2.31= positive number that reaction is spontaneous.

Cathode - anode!

Question 10

metals corrode to form what?

Answer 10

their ions, salts, oxides and hydroxides.