Sunday, 27 March 2011

How to make yourself a lovely cup of Halogenoalkanes

Bond Fission

Bond Fission is a fancy term for Breaking Bonds.

Breaking Bonds can either be:
The electrons in the bond retract and split in between the molecules to form ions. Wonderful.

The electrons go to only one molecule, forming a Radical. Dun Dun Duuuuun.
(Common in Polar Bonds)
Radicals are generally provoked when a bond absorbs an unusual amount of energy, such as UV energy, this is why this happens quite a bit in the upper Stratospheric zone. This relates to Ozone damage et cetera. 

How Radicals form (Kinda, in context of Chlorine):

note: Radicals are bad because they're very reactive, and they can release chain/sequence reactions, deforming naturally occurring bonds, such as O3 (Ozone):

Initiation (When the first radical is made):
Propagation (When a radical reacts to make more radicals):
Termination (When 2 radicals react together to make a stable compound):

Saturday, 12 March 2011


Halogenoalkanes are Hydrocarbon compounds in which one or more hydrogen atoms in an Alkane have been replaced by halogen atoms (Fluorine, Chlorine, Bromine or Iodine).

For example:

Naming Halogenoalkanes:

Name the longest Carbon chain as for branched chain Alkanes.

Carbon atoms bonded to halogen atoms are given the lowest possible numbers.

Halogens are named before alkyl groups :
Fluorine atom is named as Fluoro.
Chlorine atom is named as Chloro.
Bromine atom is named as Bromo.
Iodine atom is named as Iodo.

For more than one of the same Halogen:
di = 2
tri = 3
tetra = 4

For more than one type of halogen, name them alphabetically:
Bromo named before Chloro named before Fluoro named before Iodo

Physical Properties of Halogenoalkanes:

The C-Halogen bonds are polar.
The Halogenoalkanes are immiscible in water.
The bigger the chain, the higher the boiling point.
The bigger the Halogen, the higher the boiling point.
The more Halogens, the higher the boiling point.

The more reactive a Halogen, the more stable the compound it makes is.
For example, Fluorine is very reactive. Fluorobutane isn't.

Chemo-Industrial Calculations

Courtesy of BBC bla bla bla

Chatting about Moles, Atom Economy and Yield.

Friday, 4 March 2011

Diploes (Intermolecular Bonding)

Dipolar molecules are any molecules that have a positive end, and a negative end.

When a molecule has a dipole it is polarised.

This is a force that binds molecules together.

This is what guides physical states (Whether something is Solid, Gaseous or Liquid etc.)

There are three types of Dipoles:

1- Permanent Dipoles:
HCl molecules have a dipole.
When two atoms sharing a (covalent) bond, and have a really, really, really different electro-negativity (Different charges), they become permanent dipoles, because they're so, so, so attracted to each other. Cute.

HCl has a permanent dipole as Cl has a much higher electronegativity than H.

2- Instantaneous Dipoles:
This happens completely randomly.
This is when the electrons in a molecule suddenly move to one side of the "Cloud", instead of being evenly distributed.

When this happens next to other molecules, Induced Dipoles occur!

3- Induced Dipoles:
This happens completely randomly.
This is when the electrons in a molecule suddenly move to one side of the "Cloud", instead of being evenly distributed.

Badass elements: Fluorine and Bromine

Fluorine is the most reactive Halogen, and is in fact more reactive than most elements in the periodic table as far as I'm aware (Except the badass radioactive ones).

Fluorine is too reactive to be put in glass, this is just an imitation of what Fluorine gas looks like.

Fluorine is a pain to transport, because it tends to react with whatever you put it in.

Fluorine is an oxidising agent with an insane charge density.

Tends to chill around in nature as Calcium Fluoride.
Calcium Fluoride physically looks much like Titanium(IV)Oxide.

CaF  +  H2SO4   --> CaSO4 + 2HF
Uses include Toothpaste, HCFC making and facial surgery.

Bromine is another halogen, named after "Bromos", greek for "Stench".
Bromine can only be transported in lead tanks, or similar, which are very heavy. Therefore, it's often transported by rail.
Mmm Gas-y

Uses include Flame retardants (TBBA), Pharmaceutics, Pesticides, Dyes, Fumigants like Bromoethane.

Industrial terminology

Raw Material: The basic stuff. E.g. Logs, Brine, Rock, Ores...etc
Feedstock: Semi useful things made from the raw materials, such as Chlorine.
BiProduct: Something you accidentally made.
CoProduct: Something you accidentally made, but is useful.


Making Titanium(IV)Oxide:

Rutile Ore, Rock salt and water ----> Titanium(IV)Oxide, Chlorine and Water ---->Titanium Oxide.

The Rutile Ore, the rock salt and the water are Raw Material/Feedstock. Because it's the input.
Titanium(IV)Oxide is the product. Because it's what you wanted.
Chlorine is the CoProduct. Because it's not what you wanted, but you can still use it for something else.

Extraction of Chlorine

Chlorine lays around in the form of Sodium Chloride.

1- We could use electrolysis to extract it. This is called the "Membrane Cell" method.

  • Developed in the 1980s.
  • Kinda costly because the semi periemable membrane is made of Teflon.
  • Low running cost.
  • Produces butt loads of Chlorine.
  • Less environmental effects than the Mercury Cell.

Electrolysis is separating 2 substances in an ionic aqueous solution using electric current.
Ions have a charge. When electricity starts running through the aqueous solution, the positive ions get attracted to the cathode (Negative side) and the negative ions get attracted to the Anode (Positive side).

Feedstock is Brine
Co products of Chlorine2 are Hydrogen2 and NaOH

Half equations:
2Cl- --> Cl2 + 2e- (Anode)

2H2O + 2e- --> 2OH- + H2 (Cathode)

2- The Mercury Cell is another way of extracting Chlorine. 

  • Mercury is poisonous.
  • The Mercury cell is very effective.
  • More costly than the Membrane Cell.
  • Uses 1.05g of Mercury per ton of Chlorine.
  • Becoming less popular with the Membrane Cell around now.
3- There's another method for extracting Chlorine, the Diaphragm Cell.

Works in the same exact way as a Membrane cell, only that it has a Diaphragm in the middle, as opposed to a Membrane. They're both Semi Permeable textures anyway.

Sunday, 27 February 2011

Aqua Regia

One of those things that you stumble upon on the internet, add to your favourites because you think it's interesting and never go back to.

Have a look.

Monday, 7 February 2011

Electronic Structure. A bit further detail.

Basically, In GCSE, you were lied to because you were (And probably still are) too dumb to understand the concept that orbitals are fake. Kinda.

Electrons are actually held in Subshells within Shells.

Capacity Hierarchy:
Sub-shells > Shells > Orbitals

So starting from basic to complex:

  • Shells are the big "Circle" or "Orbit" around the element.
  • Sub-shells are smaller shells that form the big Shells. 

  • The number of Subshells in a Shell = The number of the shell. 
Like this!
  • For example, Shell 3 (n=3) has 3 sub orbitals.
  • Subshells come in different capacities.
'S' can hold  2 electrons.
'P' can hold  6 electrons.
'D' can hold 10 electrons.
'F' can hold 14 electrons.

  • Orbitals are the very small thing. A part of a subshell. There is a maximum of 2 electrons held in each orbital. 

In summary, this is the hierarchy of electronic configuration of Sub-shells:
For example (Putting this into use)
The electronic sub-shell configuration of Gold:
1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6, 4d10, 4f14, 5s2, 5p6, 5d10, 6s1

Where as the first number (Before the letter) is the Energy Level.
Where as the second number (After the letter) is the Number of Electrons held in the subshell.

Putting it into order to make it look tidy:
 The things this can tell us:

Friday, 28 January 2011


The Halogens are 5 non metallic group 7 elements in the periodic table. They have slightly different properties because of their electronic setting (having 7 electrons in their outermost shells).

The most significant property of Halogens is their greatly high reactivity.

In terms of patterns and trends, as you move further down the group, electronegativity and reactivity decreases, while boiling points increase. (Exception of Astatine, because that stuff's radioactive).

Halogens have a high electronegativity, and are particularly reactive to form stable ionic crystals (Salts) as the name suggests, halo meaning salt and gen meaning to form.

**Sodium Chloride is the most abundant Halogen-produced Salt**

Sodium Chloride Crystals

The charge density of the nucleus of Halogens is important because it shows that they have a high proton charge, which grants them a good electronegativity making them ideal anions, for pairing with the 1st group cations such as Na+.

Halogens, as they have 7 electrons in their outer shells, have an oxidation number of -1, with a few exceptions, for example if it was binded with Oxygen or another Halogen that is more reactive, with Fluorine being the most reactive one.

The difference in reactivity between the group 7 elements is within the fact that they're in consecutive periods, meaning there's a hierarchy relating between the number of outermost shells and the reactivity of the element. This is relating to the idea that more rings around the nucleus make the outer-most shell further away from the centre point of electronegativity, so the pull is spread over a large area decreasing its concentration.

Halogens as oxidation agents follow this general form:

Sunday, 23 January 2011

Electrophilic Addition

Electrophilic addition is basically this:
Like when you have a retarded bond that decides to jam itself into an unsaturated alkene. A bit like that relative you never liked. 

This happens in some stupid stages you're meant to remember. As if it'll mean anything to you in life.

Stage number one. The retarded bond ATTACKS the chilling alkene.

As the chilling alkene gets shanked by the retarded bond, one of its bonds snaps off. The electron's left hanging there.
As the bond's snapped off, the retarded bond makes advantage of this via exploiting the open port, as the following diagram illustrates.
And then we get this:

And then,
So, we end up with this: