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Derivation of the Phase Rule

Derivation of the Phase Rule:                                        According to this rule, for any equilibrium thermodynamic system, the sum of the number of degrees of freedom(F) and the number of phases(P) are equal to the sum of number of independent component ‘C’ and the number of external factors n(T and P) affecting the physical state of the system.            F+P=C+n   Or ,     F+P= C+2        where ( n=2 )   Or ,    F= C-P+2    (Gibbs phase rule) Let us consider a heterogeneous system in equilibrium having C components (C 1 ,C 2 ,----C c ) distributed in P phase (P 1 , P 2 , ----P p ). The number of degree of freedom = Total number of variables   - The number of factor define by the system Step-I :   Determination of the total number of variables:                                                  Let us consider, a system which is having two component C 1 and C 2 . If the molar concentration of one component is known than that of other can be calculat
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Phase Rule

Phase Rule                     The phase rule is an important tool in the study of heterogeneous equilibrium. It relates the condition which mistake specified to describe the state of a system equilibrium. A substance can exist in various states depending on the external conditions. For example, water can exist in the form of a solid, liquid, and vapor. A change in the state of a substance is called phase transition. Equilibrium is a system in which phase transitions occur in addition to a chemical process is called phase equilibrium. Explanation of the Terms Involved in Phase Equilibrium or Terminology:- 1.       Phase (p):                               A phase is defined as the homogeneous parts of heterogeneous system. which can be separated from each other by simple mechanical method by means of a definite boundary. A phase is a physically distinct and mechanically separable part of a system. Example: i.                     Water exists in three forms –ice
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Properties of Lubricants

Properties of Lubricants:- Lubricants have several properties, some important properties are given below:- 1.       Viscosity:                              It is the property of a liquid or a fluid by virtue of which it offers resistance to its own flow. If two layers of a liquid separated by a distance’s and moving with a relative velocity difference ‘v’ then force per unit area(f) required to maintain this velocity difference is given by-                                                 f=nv/d Where n is the coefficient of viscosity. Viscosity is the most important property of any lubricating oil. If the viscosity of the oil is too low a liquid oil film cannot be maintained between two moving surfaces and excessive wearing takes place. Determination of Viscosity: The apparatus which is used to determine the viscosity is known as viscometer. In industry viscosity of lubricating oil is determined by Redwood, say bolt and Angler instrument. In the Redwood viscometer
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Additives For Lubricants

Additives For Lubricants There are lack of properties of single lubricating oil so the properties of lubricants may be improved by adding some specific suitable compounds, such type of compounds which are used to improve the properties of lubricants are known as additives for lubricants. Some important additives are listed below. (i)                  Extreme pressure additives:   These additives either get absorbed on the metal surface or react with the metal to form a layer having low shear strength on the metal surface and prevent wearing and tearing. They also protect them from welding and seizure under extreme pressure conditions. For example fatty ester, acids, organic chlorine compounds, metallic soaps etc. (ii)                Viscosity Index improves: The prevent the oil from thickening at low temperature and thin at higher temperature. Long chain polymers like polyesters, polystyrene etc are used as viscosity index improves. (iii)              Anti-Oxidants: The
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Classification Of Lubricants

Classification Of Lubricants: According to the state of lubricant there are classified into the following classes: (i)                  Liquid lubricants or Lubricating oils (ii)                Semi-solid Lubricants, and (iii)              Solid Lubricants These are describing below one by one. (i)                  Liquid Lubricants:                                 The main function of lubricating oils is to reduce friction or wear between two moving metallic surfaces by providing a continuous film in between them. Liquid lubricants are further classified as:- (1)    Animal Oils and Vegetable Oils (2)    Minerals Oils(Petroleum oil) (3)    Blended Oils(Compounded Oil), and (4)    Emulsions (1)        Animal Oils and Vegetable Oils:                           Animal and vegetable oils are very important having good oiliness and obtained from the animal and vegetable kingdom contain glycerides of higher fatty acids. Before developing the petroleum
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