Question: How do you separate iron related material and a non-magnetic material in a mixture?

Answer: Use magnets. This is because iron is a magnetic material and it can be attracted to the magnet while the non-magnetic material can't. So therefore, the iron can be separated fron the non-magnetic material.

Question: When a solid is dissolved in water you can separate the two by?

Answer: You can separate them by evaporating the water. Once all the water has evaporated, the solid would 'emerge'. We can also use filration.

Question: Separate solid that cannot dissolve in liquid.

Answer: There's serveral methods for this one. If the solid is magnetic, we can use a magnet to separate the solid from the liquid. If not, we could use a filter. Distillation is fine too. We can also evaporate the water, leaving the solid behind.

Question: Separate Liquid and Liquid.

Answer: We can use distillation and fractional distillation.

Question: Air and petroleum?

Answer: Use fractional distillation or distillation because both of them have different boiling points.

I'll post the other 2 videos the next time. (:

Since there's allotrope for carbon, I thought there must be allotrope for metal etc.
Guess what? There are allotrope for oxygen, sulphur, silicon, tin and many more.

Allotrope of iron:

Iron represents perhaps the best-known example for allotropy in a metal. There are three allotropic forms of iron, known as alpha, gamma, and delta.
As molten iron cools down it crystallises at 1538°C into its delta allotrope, which has a body-centred cubic (BCC) crystal structure[1]. As it cools further its crystal structure changes to face centred cubic (FCC) at 1394°C, when it is known as gamma-iron, or austenite. At 912°C the crystal structure again becomes BCC as alpha-iron also known as ferrite, is formed, and at 770°C (the Curie point, Tc ) the iron becomes magnetic as alpha-iron, which is also BCC, is formed.

source: http://en.wikipedia.org/wiki/Allotropes_of_iron
-----------------------------------------------------------------------------

Allotrope of sulphur:

Sulphur is found widely distributed in earth's crust. It is found in vast underground beds of 99.8% pure uncombined sulphur and in many sulphide minerals such as galena,pyrite ,sphalesite and various calcium, magnesium and other sulphates.Sulphur is also present in organic compounds.It is found in animals and vegetables such as onion, garlic, mustard, eggs, proteins etc. Sulphur also occurs along with hydrocarbons such as coal and petroleum.

There are 3 allotropic forms of sulphur:
1)monoclinic
2)plastic
3)rhombic

source: http://www.blurtit.com/q175417.html

---------------------------------------------------------------------------------------------
Allotropes of phosphorus:

Elemental phosphorus can exist in several allotropes; the most common of which are white and red. There are also violet and black phosphorus, and gaseous diphosphorus.

<- white phosphorus structure.

-->White phosphorus, or yellow phosphorus, or simply tetraphosphorus (P4) exists as individual molecules made up of four atoms in a tetrahedral arrangement, resulting in very high ring strain and instability. It contains 6 single bonds.

<-- red phosphorus structure.

-->Red phosphorus may be formed by heating white phosphorus to 250°C (482°F) or by exposing white phosphorus to sunlight. Phosphorus after this treatment exists as an amorphous network of atoms which reduces strain and gives greater stability; further heating results in the red phosphorus becoming crystalline. Red phosphorus does not catch fire in air at temperatures below 240°C, whereas white phosphorus ignites at about 30°C.