Elements of the Sea

Notes on Elements of the Sea. 

HideShow resource information
  • Created by: H
  • Created on: 12-04-13 10:50
Preview of Elements of the Sea

First 396 words of the document:

Halogen Benefits Risks
Fluorine Used to make plastics such as PTFE Element is highly reactive and handling must be
Applied to toothpaste to strengthen tooth paste to a minimum.
Used to make HCFC
Chlorine An important intermediate in the manufacture of Pesticides can accumulate in the environment (
hyrdochloric acid and chlorinated solvents. DDT)
Used in the plastics industry (for PVC and CFCs destroy stratospheric ozone.
Used in water treatments and to make
pesticides, medicines and bleach.
Bromine Used in the manufacture of flame retardants, Organic Bromine compounds can destroy ozone
agricultural fumigants and in photography. stratosphere.
Iodine Used in antiseptics, germicides and dyes.
Iodine 131 is used to detect thyroid disease.
Ions in Solid and solutions
Chem Ideas 5.1
[these notes were lost]!
Ionic equations
Ions in solution behave independently ­ and this includes when they are involved in chemical
reactions. If two solutions react to form a solid, a precipitation reaction is said to have occurred.
Spectator ions do not take part in the reaction so are not included in the ionic equation.
These rules will help you to predict whether and ionic precipitation reaction will take place when two
solutions are mixed.
All nitrates are soluble in water
all chlorides are soluble in water except AgCl and PbCl2
all sulfates are soluble in water except BaSO4, PbSO4 and SrSO4.
All sodium, potassium and ammonium salts are soluble in water.
All carbonates are insoluble in water except (NH4)2CO3 and those of group one.
Neutralisation reactions can also be summarised using ionic equations. When an acid and alkali reacts
with sodium hydroxide the ions involved and the products are:
H+(aq)+Cl-(aq)+Na+(aq)+OH-(aq) ->H2O(l)+Na+(aq) + Cl-(aq)
Ionic equation: H+(aq)+OH-(aq)->H2O(l).
Calculations of concentrations
Concentrations can be measured in grams per cubic decimetre (gdm-3)
Using concentrations in calculations
a titration is a method of quantitively finding the
concentration of a solution by reacting a known volume of it
with another solution of a known concentration. The end
point of a reaction is often detected by the use of an

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

A fixed volume of solution of unknown concentration is placed in a conical flask using a
A few drops of a suitable indicator are added to the mixture and placed on a white tile (to
see the end point clearly).
The solution of known concentration is added slowly from a burette with constant swirling.
As you approach the end point, add the solution from a burette drop wise.
After a rough titration, accurate titrations follow until concordant results are gained.…read more

Page 3

Preview of page 3

Here's a taster:

There is a sharp jump in ionisation enthalpy when an electron is removed from a full electron
shell. Aluminium has an electron arrangement of 2.8.3 so after the third ionisation enthalpy,
the ionisation enthalpy increase lots!
Oxidation and Reduction
when an oxidation and a reduction reaction occur simultaneously, this is called a redox reaction.…read more

Page 4

Preview of page 4

Here's a taster:

Appearance and Volatility Solubility in Solubility in
state at room water organic solvents
Fluorine (F2) Pale yellow gas Gas reacts with water Soluble
Chlorine (Cl2) Green gas Gas Slightly soluble to Soluble to give
give a pale green pale green
solution solution
Bromine Dark red liquid Liquid quickly Slightly soluble to Soluble to give a
forms brown gas give red-brown red solution
on warming solution
Iodine (I2) Shiny black solid Sublimes on Barely soluble, Soluble to give a
warming to give gives a brown…read more

Page 5

Preview of page 5

Here's a taster:

An s subshell has 1 orbital holding a maximum of 2 electrons
A p subshell has 3 orbitals holding a maximum of 6 electrons
A d subshell has 5 orbitals holding a maximum of 10 electrons.
The arrangement of electrons in shells is called the electronic configuration.
Orbitals are filled in order of increasing energy
Where there is more than one orbital at the same energy, the orbitals are first occupied by single
electrons then paired.
Electrons in singly occupied orbitals have parallel spins.…read more

Page 6

Preview of page 6

Here's a taster:

PD-PD bonds are responsible for holding polyester molecules together.
The degree in which an atom of an element attracts an element is called its electronegativity. The
more electronegative an element, the greater attraction for electrons. Order for some common
elements is:
F>o>Cl>Br and N>I>S>C>H
The difference between the electronegativity's of C and H is so small that the bonds between them
can be considered non-polar.
Bond polarity and polar molecules
A polar molecule is one that has a permanent dipole, for example ethanoic acid.…read more

Page 7

Preview of page 7

Here's a taster:

The chloroalkane is immiscible in water and forms a layer above the aqueous products. There are 5
stages in purification of the chloroalkane:
The upper layer containing the chloroalkane is run off into a clean beaker.
The chloroalkane is shaken with a solution of sodium hydrogencarbonate to remove any acid
Chloroalkane layer is run off for a second time
Anhydrous sodium sulfate (a drying agent) is added to remove any water.
Chloroalkane is purified by distillation.…read more

Page 8

Preview of page 8

Here's a taster:

Raw material -------------------- feedstock ------------------------- products
rock salt brine Sodium, hydroxide, hydrogen
(sodium chloride solution) and chlorine
Chlorine is the desired product. Sodium hydroxide and hydrogen are co-products ­ produced at the
same time as the desired product via the same reaction. As the amount of desired product increases
so do the co-products. In this case they are useful products that can be sold to generate further
profits to the manufacturer.
Many reactions produce by-products ­ these are the result of unwanted side reactions.…read more

Page 9

Preview of page 9


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »