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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 −.
The Van 't Hoff equation relates the change in the equilibrium constant, K eq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, Δ r H โ, for the process. The subscript r {\displaystyle r} means "reaction" and the superscript โ {\displaystyle \ominus } means "standard".
Thus, an endothermic reaction generally leads to an increase in the temperature of the system and a decrease in that of the surroundings. [1] The term was coined by 19th-century French chemist Marcellin Berthelot. [3] The term endothermic comes from the Greek แผνδον (endon) meaning 'within' and θερμ- (therm) meaning 'hot' or 'warm'. [4]
Using the thermochemical equation of variables as above, one gets the following example. + = One must assume that needs to be multiplied by two in order for the thermochemical equation to be used. All the agents in the reaction must then be multiplied by the same coefficient, like so:
The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Thermal decomposition is a chemical reaction where heat is a ...
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.
A plot illustrating the dependence on temperature of the rates of chemical reactions and various biological processes, for several different Q 10 temperature coefficients. The rate ratio at a temperature increase of 10 degrees (marked by points) is equal to the Q 10 coefficient.
Thermochemistry is the study of the heat energy which is associated with chemical reactions and/or phase changes such as melting and boiling. A reaction may release or absorb energy, and a phase change may do the same. Thermochemistry focuses on the energy exchange between a system and its surroundings in the form of heat. Thermochemistry is ...