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The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure. Units of solubility are given in grams of substance per 100 millilitres of water (g/100 ml), unless shown otherwise.
Sodium sulfate is a typical electrostatically bonded ionic sulfate. The existence of free sulfate ions in solution is indicated by the easy formation of insoluble sulfates when these solutions are treated with Ba 2+ or Pb 2+ salts: Na 2 SO 4 + BaCl 2 → 2 NaCl + BaSO 4. Sodium sulfate is unreactive toward most oxidizing or reducing agents.
Barium chloride is extracted out from the mixture with water. From water solutions of barium chloride, its dihydrate (BaCl 2 ·2H 2 O) can be crystallized as colorless crystals. [2] Barium chloride can in principle be prepared by the reaction between barium hydroxide or barium carbonate with hydrogen chloride. These basic salts react with ...
A neutralization reaction is a type of double replacement reaction. A neutralization reaction occurs when an acid reacts with an equal amount of a base. This reaction usually produces a salt. One example, hydrochloric acid reacts with disodium iron tetracarbonyl to produce the iron dihydride: 2 HCl + Na 2 Fe(CO) 4 → 2 NaCl + H 2 Fe(CO) 4
Enthalpy change of solution in water at 25 °C for some selected compounds [2] Compound ΔH o in kJ/mol; hydrochloric acid: −74.84 ammonium nitrate +25.69 ammonia: −30.50 potassium hydroxide: −57.61 caesium hydroxide: −71.55 sodium chloride +3.87 potassium chlorate +41.38 acetic acid: −1.51 sodium hydroxide: −44.50