Unit 4 Oxidation/Reduction/Redox

Oxidation

When something loses electrons.

Oxidation original definition

Something reacting with oxygen

are metals gainers, or losers?

Metals are losers

Are nonmetals gainers or losers

Gainers

Electrons are on the product side for which reaction

Oxidation

What does a half reaction mean?

Half of what is happening

What happens during a correct oxidation?

Particles are conserved and charge is conserved. This means that the charge on the left equals the charge on the right.

which side do you add the electrons to during an oxidation?

Product side

Does rusting indicate oxidation or reduction?

Oxidation

Reduction

Gaining electrons

What is ore

Lots of metals combined together iron is an example of this

Where are the electrons attached during a reduction?

The reactant side

What is the reductions original definition?

When a mineral is converted into a pure metal, it also said the mass would go down when an anion is removed from the metal

What is a redox reaction?

It is an oxidation reduction, that involves the transfer of electrons between two substances.

Are oxidized metals, losers, or gainers

Losers

Do metals get oxidized or reduced?

Oxidized

Do nonmetals get oxidized or reduced

They get reduced

Do nonmetal ions get oxidized or reduced

Oxidized

Do metal ions get oxidized or reduced

Reduced

What must be equal before you add together half reactions

The electron coefficient

Can you ever have a subscription on the product side?

Never

What are the noh sevens?

Nitrogen, oxygen, hydrogen, bromine, argon, iodine chlorine

If you end with a metal, is it a oxidation or reduction?

Reduction

Is a redox a type of reaction

Yes

What happens in a redox reaction?

A gains or loses an electron

What is an oxidation number?

A number assigned to an atom that represents a hypothetical charge if the bonds were completely ionic

What is the purpose of an oxidation number?

To keep track of the electron transfers and redox reactions

What is rule number one

All elements have an oxidation number of zero

What is rule number two

Monoatomic ions have the charge of their oxidation number

What is rule three

Alkali or group one in a compound are +1

What is rule four

Alkaline earth metals or group 2 in a compound are +2

What is rule five

Oxygen in a compound excepting peroxide is -2. Hydrogen in a compound excepting hydrides is minus one

What is rule six

Halogens in a compound or minus one Chalcogens in a compound are -2. Nitrogen and other nitrogen families and compounds are normally -3

What is rule seven

This is the most important rule. It says the sum of the oxidation number is in a particle adds up to the overall charge of that particle

What are examples of chalcogens and what are they

They are elements in group 16 of the periodic table. They include oxygen, sulfur and selenium.

Where are the Alkalise or group ones on the periodic table

They are the first row, excluding hydrogen

Where are the alkaline Earth metals

They are the second row

What is the difference between Monatomic ions and elements

Monatomic have charges an element standalone with a net charge of zero

What is a peroxide used to do?

Bleach or dye hair

What does the oxidizing agent do?

It causes the oxidation, it is reduced itself, written with the whole compound. It also gets reduced in the process. It also gains electrons.

What happens to the reducing agent?

It is oxidized in the process, and causes the reduction by giving away electrons.

What does a reducing agent cause?

It causes a reduction by giving electrons to another

How can you tell if an equation is a redox reaction?

If there is a change in the oxidation number between the reactants and products, which means the electrons are transferred

Are no sevens in their squared form pure elements

Yes, they are

Are non-no sevens pure elements in their squared form

No, this is a molecular form

When you are solving a non-redox can you have charges that are equal and still have no change?

Yes

What is the difference between a redox and no non-redox

Redox has electron transfers and the oxidation number changes non-redox reactions have no electron transfer, and the oxidation number stays the same

Redox and non-redox are examples of What?

Reactions

Is it possible to tell the difference between redox and non-redox unless you calculate the oxidation number

No

Does it matter if the equations are balanced in redox or non-redox

nope

Is the charge for one or multiple (with subscripts)

No matter how big the subscript your charge should only be for one

Should I change the oxidation state based off coefficient?

Nope, the charge should stay the same

If there is no charge to set equal to what should you set equal to

0

What are the only two set elements?

H and 0

What is the charge of any element that has any number of subscripts and coefficient but no set charge

0

Can Cl, or any other non row 1-2 element have a changing charge

yes

What are the only set charges?

row 1, 2, O, and H

Who does a peroxide do on a cut?

It bubbles

If a problem asks for the oxidation or reduction of a half reaction, what should you write?

only one element, the one that is changing

What does a reduction look like in a half reaction?

Electrons decrease from left to right, negative electrons are added to the other side, causing a subtraction ex. +7 → +4

What does a oxidation look like in a half reaction?

Electrons increase from left to right, losing an electron ex. 2+ → 3+

How to write the oxidation and reduction agents?

Write out the full chemical like this ex. Mg (in MgNOH)

At the top of the metal activity chart, does it represent more or less active metals.

It represents the most active metals.

Is the top or the bottom of the metal chart the best losers.

the top

Every metal reacts with a ____ below it?

ion

What is the salt bridge?

It allows the flow of ions/electrolytes, is made of an ionic compound. The salt must not react with the chemicals used. It also keeps both sides of the battery electrically balanced.

What is the external circuit?

It is the wire used across the top of the two sides. It allows electrons to flow from one electrode to another. Basically:electrons (e⁻) moving through wires.

What is the internal circuit?

the path inside the battery that completes the electrical circuit by allowing ions (not electrons) to move between the two half-cells. Basically:ions moving through the salt bridge or electrolyte to maintain charge balance.

How are batteries designed?

To have electrons run through them.

How do you know which side will lose?

Whichever one is higher on the metal activity scale.

What is an anode?

An anode is one of the two electrodes in an electrical device where current either enters or leaves a system, depending on the type of device. It is the electrode where oxidation occurs. It also attracts anions.

What is a cathode?

A cathode is the electrode where reduction occurs (gain of electrons) in any electrochemical or electronic device. Reduction happens at the cathode, which also attracts cations.

Where do the electrons move through to get from anode to cathode?

The external circuit

What happens if the electrons cant move through the wire without restriction?

the battery turns off

Which side of the battery get heavier over time and why?

The cathode gets heavier, it happens because it gains a metal coating.

In a battery which side (cathode, anode) is positive and which is negative?

cathode is positive, anode is negative

What happens to the anode over time?

It slowly deteriorates as it undergoes oxidation.

What are the 2 ways that a battery can die?

1. All ions turn to solid coating (on the cathode side)

2. You run out of the anode chemical

How does battery recharging work?

Electrons are forced back the opposite direction where they dont want to go, it flips from oxidation to reduction. It turns the coating back into ions and then it once again resumes its normal flow.

Once the metal coating starts to appear, can you ever fully get rid of it?

No every battery dies.

How does the on/off switch work?

When you turn it on you complete the circuit, allowing the electrons to flow. When you turn it off, the circuit is broken and the flow of electrons is paused.

As the tendency to lose electrons increases as you go up the metal reactivity chart, what also increases?

the oxidizing nature of it (rusting or corrosion)

What do you observe if a reaction occurs between something above the other on the reactivity chart

no change

What chemical is air

O2

how do you detect the evolution of hydrogen gas from a reaction mixture?

gas is evolving is the splint starts burning

What is a voltaic cell?

basically a battery, oxidation occurs at the anode and reduction occurs at the cathode

What is Cl charge most of the time

-1