Chemistry - Oxidation and Reduction Flashcards Part 1

addition or removal of oxygen
transfer of electrons
oxidation number

Gaining oxygen

loss of oxygen

the removal of oxygen or the addition of hydrogen

a more reactive metal will displace a less reactive metal from a compound

produce:white hot molten iron in remote locations.
alminium + Iron(III)oxide -> Iron + aluminium oxide
Alminium removes oxygen from iron oxide. The iron is reduced. Alminium is oxidised

A more reactive metal will displace a less reactive metal from a solution of one of its salts

Magnesium + copper(II) sulfate -> copper + magnesium sulfate.
The blue colour of the copper fades as its being used up.the copper metal begins to form.

oxidation of an element takes place when it loses electrons

reduction of an elemnet takes place when it gains electrons

When one reactant loses electrons the other has to gain electrons

oxidation and reduction takes place.zinc becomes covered with a reddish deposit which is the copper metal.The blue colour of the solution fades-which implies the copper metals are being used up.This is a redox reaction and a displacement reaction.

a reaction where oxidation and reduction occour simultaneously.( one cannout occour without the other)

substance that brings about oxidation in other substances

substance that brings about reduction in other substances

A the charge that an stoms has or appers to have when electrons are distrubuted according to certain rules

A the force of attraction that an atoms has for a shared pair of electrons

A increase in oxidation number

A decrease in oxidation number

A oxygen oxidation number is always(-2).

expect in peroxides(bonded with hydrogen)

expect with a more electronegative element.

Hydrogen ON number is always +1

expect in metal hydrites where its -1

halogens ON is always -1

expect bonded to a more electronegative element

an element that forms at least one ion with a partially filled d sublevel

A good conductors of heat and electricity

hammered or bend into shape easily

high melting points

hard + tough

high densities

less reactive than alkali metals

form coloured ions of different charges

some are very unreactive

many used as catlysts

A hyprogen peroxide (H2O2) used to bleach hair

(coloured pigment + H2O2-> colourless hair pogment + H2O

chlorine in swimming pools.Cl2 is oxidising agent

household bleaches. Sodium hypochloride (NaClO)

the halogens are very reactive elements and cannot exist in a uncombined form. They act as oxdising agents (take an electron from another element)

clorine is the strongest non dangerous element. Its capable of releasing bromine and iodine form a solutions of its salts

F>Cl>Br>I>At

Pale green

Yellow/ orange

Brown/red

Colourless

Colourless

Colourless

all three halogen solutions are able to oxidise iron(II) ions into iron (III) ions.

in two seperate test tubes.

add iron(II) sulfate and iron(III) chloride

add sodium hydroxide (NAOH)

Iron (II)sulfate + NaOH = Fe(OH)2 -> green percipate

Iron (III) chloride + NaOH = Fe(OH)3 -> brown percipate

Add chlorine water to Fe(OH)2

(when Cl2 is added to the Fe2+ mixture is oxdises the Fe2+ to Fe3+ (green - brown)
conculsion: chlorine oxdises the Fe2+ ions into Fe3+ ions

So3 2- --> So4 2-

add sodium sulfite to test tube

add chlorine

(no change)

add BaCl2

(white ppt forms)

add HCl

(white ppt stays)

this proves the presence of sulfate ions

Magnesium and Zinc are respectivily reacted with a solution of copper (II) sulfate

Colour of CuSO4 at beginning Blue

Colour at end colourless

colour of ppt formed Brown

other observations Gas evolved

In both casrs the metal (magnesium/zinc) displaces the copper from its salts

Blue to colourless

No CU2+ ions present