When acids and bases are mixed in the right proportion they react with each other to give salts and water NaOH + HCl ® NaCl + H₂O Arrhenius Concept of Acids and Bases: According to Arrhenius theory, acids are substances that dissociates in water to give hydrogen ions H + (aq) and bases are substances Read more about Acids, bases and salts[…]
Free Energy Change (ΔG): The two thermodynamic quantities which affect the spontaneity of a reaction are enthalpy (H) and entropy (S). The free energy is the amount of work that a thermodynamic system can perform The free energy of a substance such as its enthalpy or entropy is a characteristic property of the substance. In any reaction, the change in free Read more about Gibbs Energy change and Equilibrium[…]
Standard states: A pressure of 1 atm and a constant temperature (25˚C) are taken as standard states. State Standard states Gas Ideal gas at the given temperature and 1 atm Liquid Pure liquid at the given temperature and 1 atm Solid Stable crystalline from at given temperature and 1 atm pressure Heat of reaction: Heat Read more about Enthalpy change, (Δr H) of reactions – reaction Enthalpy[…]
Enthalpy or Heat of Combustion: It is the amount of heat evolved or decreased in enthalpy when one mole of a substance is completely oxidized. Organic compounds containing only carbon, hydrogen, and oxygen are burnt to gaseous carbon dioxide and liquid water. For example, C2H6(g) + 3.5O2(g) → 2CO2(g) + 3H2O(l); ΔH = − 372.8 kcal Read more about Enthalpies of different Reactions[…]
1. Combination reactions: A + B → C For such a reaction to be redox reaction, either A or B or both should be in elemental form. Ex: 2 C⁺²O⁻²₂ (g) + O0₂ (g) → 2 C⁺⁴ O⁻²₂ (g) Fe0 (s) + S0 (s) → Fe⁺²S⁻² (s) 2. Decomposition reactions: Breakdown of a compound to form 2 Read more about Types of Redox Reaction[…]
It denotes the oxidation state of an element in a compound Rules to assign Oxidation number: Elements in free state have zero oxidation number.Ex: H2, O2, N2, C etc. have 0 oxidation number For ions composed of only one atom, the charge on the ion is its oxidation number. Ex: Cl– → -1 oxidation number Mg2+ → Read more about Oxidation Number Concept[…]
1. Law of conservation of mass: Given by Lavoisier: “In all chemical changes, the total mass of the system remains constant.”i.e., Matter can neither be created nor destroyed. Ex: 2H2 + O2 = 2H2O. Reactants mass = 4 + 32 = 36 g. Products mass = 2 X (2 + 16) = 36 g. Reactants mass Read more about Laws of chemical combinations[…]
A) Oxidation number method: 1. Write correct formula for each reactant & product. Ex: K2Cr2O7 + HCl → KCl + CrCl3 + H2O + Cl2 2. Write oxidation numbers for all elements K+12Cr+62O-27 + H+1Cl-1 → K+1Cl-1 + Cr+3Cl-13 + H+12O-2 + Cl02 3. Calculate the increase or decrease in oxidation number per atom Oxidation Read more about Balancing Redox Reactions[…]
Discovered by Andrews for CO2 Above a certain temperature, it is impossible to liquefy a gas. The temperature below which a gas can be compressed by applying only pressure is called critical temperature (Tc). The pressure applied to liquefy gas is called critical pressure Pc The volume occupied by one mole of the substance is Read more about Liquefaction of gases[…]
The kinetic gas equation is given as: PV = 1/3 mnc2 P = pressure V = volume M = mass of molecule n = no. of molecules present in the given amount of gas c = root mean square speed. Kinetic energy for one mole of gas is given as c = c1 + c2 + … Read more about Kinetic Gas Equation of an Ideal Gas[…]