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During electrolysis, substances like oxygen gas, chlorine gas, bromine etc. are liberated at the anode depending on the electrolytes used, while substances like hydrogen gas, copper, silver etc. are liberated or deposited at the cathode. The volume of gases liberated or mass of metals deposited depend on the amount of electricity that is passed, be it carried out on one or more electrolytes. These relationships were summarized by Michael Faraday into what are now known as the Laws of Electrolysis. Faraday's 1st Law of Electrolysis This law states that the mass of a substance deposited or liberated at the electrodes during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. Mathematically, this can be expressed as:                           m α Q ..................................(i) where, m = mass in grams (g); and Q = quantity of electricity in Coulombs (C) but,                          Q = I x t .............................

Water of crystallization (WC) is the number of molecules of water present in one mole of a hydrated salt. Example, in iron (II) tetraoxosulphate (VI)-heptahydrate [FeSO4.7H2O], there are seven molecules of water attached to a molecule of FeSO4, that is its water of crystallization. Some other examples of salts with water of crystallization include: MgSO4.7H2O - Magnesium tetraoxosulphate(VI)-heptahydrate, (Epsom Salt) CaSO4.2H2O - Calcium tetraoxosulphate(VI)-dihydrate (Gypsum) Na2CO3.10H2O - Sodium trioxocarbonate(IV)-decahydrate (Washing Soda) CuSO4.5H2O - Copper (II) tetraoxosulphate(VI)-pentahydrate (Blue Vitriol) ZnSO4.7H2O - Zinc tetraoxosulphate(VI)-heptahydrate (White Vitriol) Cu(NO3)2.3H2O - Copper (II) trioxonitrate(V)-trihydrate From the above examples, it can be observed that each salt has a definite number of molecules of water of crystallization attached to it. Therefore, it can also be defined as the definite amount of water some substances chemically combine wi

John Dalton in one of his postulations of Atomic Theory stated that atoms of the same element are alike and different from atoms of other elements . This was, however, faulted with the discovery of nucleon mass (mass number) and neutrons by Rutherford and Chadwick respectively. Studies showed that there are atoms of the same element that have the same atomic number, but different mass numbers as a result of the difference in their number of neutrons. These atoms are called isotopes and the phenomenon is known as isotopy. Examples of elements that exhibit isotopy include chlorine (Cl-35 and Cl-37), carbon (C-12, C-13 and C-14), oxygen (O-16, O-17 and O-18) etc. In reality, all elements exhibit isotopy because this explains why the relative atomic masses of elements are not whole numbers . Relative Abundance of Isotopes In a particular element, say chlorine, the two isotopes - Cl-35 (chlorine-35) and Cl-37 (chlorine-37) are present in different quantities of

Definition of Terms Solute This is a substance that dissolves in a solvent to form a solution. It can be solid, liquid or gas. Examples include common salt, sugar, copper (II) tetraoxosulphate (VI) etc. Solvent This is a substance that dissolves a solute to form a solution. It can be liquid or gas. Examples are water, ethanol, benzene etc. Solution This is a mixture of solute and solvent, i.e,          Solute + Solvent = Solution It can be homogeneous with a uniform composition, e.g, an unsaturated solution of a sodium chloride, or heterogeneous with non-uniform composition like an unsaturated solution of the same salt. Saturated Solution A saturated solution is one that holds as much solute as it can dissolve in the presence of undissolved solute particles at a given temperature. In a saturated solution, the dissolved and undissolved solutes are in equilibrium at a given temperature. Unsaturated Solution An unsaturated solution is one that can still dissolve more solutes a

The Gay-Lussac's Law of Combining Volumes states that when gases react, they do so in volumes, which are in simple ratio to one another and to the volume of the product, if any; provided temperature and pressure remain constant. It applies to only gases, which means that solid and liquid reactants and products are always ignored when applying this law. For instance, hydrogen burns in oxygen at 100°C to form steam according to the equation:        2H2(g) + O2(g) ---> 2H2O(g)          2mol      1mol           2mol          2vol        1vol            2vol          2cm^3    1cm^3        2cm^3 From the above, it implies that at 100°C, when water is in its gaseous state, 2 volumes of hydrogen gas (dm^3 or cm^3) will combine with 1 volume of oxygen gas to form 2 volumes of steam, to give a simple mole ratio of 2 : 1 : 2. Therefore, 50cm^3 of hydrogen will need 25cm^3 of oxygen to produce 50cm^3 of steam. Similarly, 15cm^3 of oxygen will require 30cm^3 of hydrogen to form 30