Redox & Electrochem: Chemistry 30

Alberta Chem 30 curriculum

what is oxidation

loss of electrons

what is reduction

gain of electrons

how do you remember oxidation vs. reduction

LEO GER or OIL RIG

what is a redox rxn

a reaction in which both oxidation and reduction occur

what is a oxidation agent and where is it on the data sheet

it is a substance that causes oxidation of another substance by being rudced (takes the e-)

it can be found on the left side of the table, the strongest at the top and the weakest at the bottom

what is a volatic cell

an electrochemical cell that produces electrical energy from a spontanious redox rxn

where does oxidation occur in a voltaic cell

anode

where does reduction occur in a voltaic cell

cathode

what charge is the anode in a voltaic cell

negative

what charge is the cathode in a voltaic cell

positive

in which direction do electrons flow in a voltaic cell

anode to cathode

what is the main purpose of a salt bridge

to maintain electrical nuetrality by allowing ions to flow between half cells

which ions move toward the cathode in the salt bridge

cations

which ions move toward the anode in the salt bridge

anions

what is an electrolytic cell

a cell that uses electrical energy to drive a non-spontaneous reaction

in a electrolytic cell, where does oxidation occur

anode

in a electrolytic cell, where does reduction occur

cathode

what is the charge of the anode in an electrolytic cell

positive

what is the charge of the cathode in a electrolytic cell

negative

what is cell potential

Ecell= The voltage produced by an electrochemical cell under standard conditions.

What units are used for cell potential

Volts (V)

How do you calculate standard cell potential

Ecell= Ecathode - Eanode

what does a positive Ecell mean

it is a spontainious rxn

what does a negative Ecell mean

it is a non-spontanious rxn

What is a Faraday

the charge carried by 1 mole of electrons

What is the value of faradays constant

9.65×10^4 C/mol e-

How is charge (Q) related to current (I) and time (t)

Q=It

What does Q mean in Q=It

Charge (columbs)

what does I represent in Q=It

Current (Amperes)

What does t represent in Q=It

Time (seconds)

How do you find moles of e- from charge

mol e-/9.65×10^4

what is the oxidation number of a substance in elemental form

0

What is the ON of oxygen in most substances

-2

what is the ON of hydrogen in most substances

+1

what is the ON of flourine in most substances

-1

How do you tell if a rxn is redox

if at least one or more compounds change ON

If ON has increased, what occurred?

Oxidation

If ON has decreased what has occured?

Reduction

What is oxidised in the following rxn

Zn^+2 + Cu —> Cu^+2 + Zn

Zn

What is reduced in the folloiwng rxn

Zn^+2 + Cu —> Cu^+2 + Zn

In Zn + Cu²⁺ → Zn²⁺ + Cu, what is the oxidizing agent?

Cu

Zn + Cu²⁺ → Zn²⁺ + Cu, what is the reducing agent

Zn

What is a ½ rxn

an equation showing either oxidation or reduction seperately

Write the oxidation ½ rxn for Zinc

Zn —> Zn^+2 + 2e-

Write the reduction ½ rxn for Cu^+2 ions

Cu²+ 2e- —> Cu

Is combustion Redox rxn

yes

Is rusting a redox rxn

yes

is cell resp. redox rxn

yes

is photosynthisis redox

yes

what does iron undergo durring rusting

oxidation

what does oxygen undergo during rusting

reduction

what is used to balance O2 ions in an acidic solution

H2O

what is used to balance hydrogen atoms in an acidic solution

H+ ions

what extra substance is in a basic solution

OH-