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Ammonium chloride is an inorganic chemical compound with the chemical formula N H 4 Cl, also written as [NH 4]Cl.It is an ammonium salt of hydrogen chloride.It consists of ammonium cations [NH 4] + and chloride anions Cl −.
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
An endothermic process may be a chemical process, such as dissolving ammonium nitrate (NH 4 NO 3) in water (H 2 O), or a physical process, such as the melting of ice cubes. [5] The opposite of an endothermic process is an exothermic process, one that releases or "gives out" energy, usually in the form of heat and sometimes as electrical energy. [1]
In 2010, a Van 't Hoff analysis was used to determine whether water preferentially forms a hydrogen bond with the C-terminus or the N-terminus of the amino acid proline. [12] The equilibrium constant for each reaction was found at a variety of temperatures, and a Van 't Hoff plot was created.
In thermochemistry, a thermochemical equation is a balanced chemical equation that represents the energy changes from a system to its surroundings.One such equation involves the enthalpy change, which is denoted with In variable form, a thermochemical equation would appear similar to the following:
Water: Gas H 2 O −241.818 Water: Liquid H 2 O −285.8 Hydrogen ion: Aqueous H + 0 Hydroxide ion: Aqueous OH −: −230 Hydrogen peroxide: Liquid H 2 O 2: −187.8 Phosphoric acid: Liquid H 3 PO 4: −1288 Hydrogen cyanide: Gas HCN 130.5 Hydrogen bromide: Liquid HBr −36.3 Hydrogen chloride: Gas HCl −92.30 Hydrogen chloride: Aqueous HCl ...
Understanding this is perhaps a "thought experiment" in chemical kinetics, but actual examples exist. A gas-phase reaction at constant temperature and pressure which results in an increase in the number of molecules will lead to an increase in volume. Inside a cylinder closed with a piston, it can proceed only by doing work on the piston.
A classical example is the decomposition of mercuric oxide to give oxygen and mercury metal. The reaction was used by Joseph Priestley to prepare samples of gaseous oxygen for the first time. When water is heated to well over 2,000 °C (2,270 K; 3,630 °F), a small percentage of it will decompose into OH, monatomic oxygen, monatomic hydrogen, O ...