Atoms, Moles, Formulae and Equations

Atom is the smallest particle of an element, which can take part in chemical reaction. Molecule is the smallest particle of an element which can exist on its own and still retain the chemical properties of that element.  Ion is an atom or group of atoms which are either positively or negatively charged due to loss or gain of electrons. First 20 elements Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Flourine Neon Sodium Magnesium Aluminum Silicon Phosphorus Sulphur Chlorine Argon Potassium Calcium Relative atomic mass of an element is the number of times the average mass of one atom of an element is greater than one twelfth of the mass of carbon 12. Relative Molecular mass of a compound is the number of times the average mass of one Molecule of the substance is greater than one-twelfth of the mass of carbon 12. Mole One mole of a substance is the amount containing as many elementary entities as the number of atoms in exactly 12 grams of carbon 12.  Note: Avogadro

11 Separation Techniques Of Mixtures

Separating techniques

Types of separation Techniques
1. Seiving: it is a separation Technique which is used to separate solids of different sizes. It is employed in garri processing industries and other industries where seiving is highly needed.

2. Decantation: it is used in separating a mixture containing a liquid and solid particles into two distict layers on standing.

3. Magnetic separation: it is used to separate magnetic substances from non-magnetic ones.
It is employed in steel industries.

4. Sublimation: it is the process whereby a substance changes directly from solid to gaseous state without passing through the liquid state

5. Filtration: it is used to separate soluble particles from liquids.

6. Evaporation: it is used to recover a solid solute from a solution.

7. Separating funnel: it is used to separate two immiscible liquids.

8. Crystallization: it is used to separate salt which decompose on heating, from their solutions. The salt crystals obtained in this way are pure and usually contain water of crystallization.

9. Distillation: it is used to recover a solvent from a solution. The solution is heated In a flask to vapourize the solvent.

10. Chromatography: it is used to separate mainly coloured substances. Here, a solvent moves over a porous adsorbent meduim to separate a mixture of solutes.

11. Fractional distillation: it is a form of distillation that is used to separate solvents based on their boiling points from their solutions.
Note: the difference in boiling point between successive fractions must be more than 10°c.