Search results
Results From The WOW.Com Content Network
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
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 −.
An endothermic process is a chemical or physical process that absorbs heat from its surroundings. [1] In terms of thermodynamics, it is a thermodynamic process with an increase in the enthalpy H (or internal energy U) of the system. [2] In an endothermic process, the heat that a system absorbs is thermal energy transfer into the
Van 't Hoff plot for an endothermic reaction. For an endothermic reaction, heat is absorbed, making the net enthalpy change positive. Thus, according to the definition of the slope: =, When the reaction is endothermic, Δ r H > 0 (and the gas constant R > 0), so
Endothermic reactions absorb heat, while exothermic reactions release heat. Thermochemistry coalesces the concepts of thermodynamics with the concept of energy in the form of chemical bonds. The subject commonly includes calculations of such quantities as heat capacity, heat of combustion, heat of formation, enthalpy, entropy, and free energy.
Endothermic gas is a gas that inhibits or reverses oxidation on the surfaces it is in contact with. This gas is the product of incomplete combustion in a controlled environment. An example mixture is hydrogen gas (H 2 ), nitrogen gas (N 2 ), and carbon monoxide (CO).
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 ...
An example of a spontaneous (without addition of an external energy source) decomposition is that of hydrogen peroxide which slowly decomposes into water and oxygen (see video at right): 2 H 2 O 2 → 2 H 2 O + O 2. This reaction is one of the exceptions to the endothermic nature of decomposition reactions.