Chemistry Unit 3

does pure water conduct electricity

Even absolutely pure water has a non-zero conductivity level due to the existence of 1 ion per 5 million water molecules.

what happens to the [H3O], pH [OH], and pOH the more basic a solution

there is less H3O, a higher pH and [OH] but a low pOH

what happens to the [H3O], pH [OH], and pOH the more acidic a solution is

the h3o is greater pH is less, oH- is less, and pOH is greater

Kw

1.0×10^-14 at standard temp for the ion product of water.

what should you do if an acid and base is weak to solve for concentrations

you must set up an ICE table if it is weak

what happens to Ka as a solution is more acidic

the stronger the acid the greater the Ka value

conjugate base of a weak acid

is a weak base

to keep the blood pH within range what must the blood contain

an acid to react with any OH- added and a base to react with any H3O added, these protective acids and bases must not destroy each other

pH buffer

Any solution that contains significant amounts of a weak acid AND its conjugate weak base will be resistant to pH changes

What are some advantages of this “voltaic cell,’ compared to putting a zinc bar in copper solution?

-You can measure the voltage

-You can mix and match the beakers (half cells)

half cells

can be mixed and matched to create electrochemical cells Different cells give different voltage reactions

anode

oxidation site

cathode

reduction site

T or F: nThe half-cell with the most positive standard reduction potential is always the anode in a spontaneous reaction (voltaic cell).

f its the cathode

waterfall analogy

nThe higher E_cell, the more work that can be done by the electrons on their way to the cathode.

nFree energy = max. work that can be obtained

nWhat other qualities of a waterfall besides its height influence the amount of work that can be done by the water?

nVolume

nPressure

nElectrical charge

nvoltage

relation between Ecell and log Q

the greater the Ecell the smaller the log Q is