The production of chemical products is based on the occurrence of chemical reactions. A chemical reaction is a process that causes one group of chemical substances to be chemically transformed into another group of chemical substances. Traditionally, the changes involved in a chemical reaction only involve the formation of chemical bonds between atoms and the position of electrons in the break, while the nucleus is unchanged, and can usually be described by chemical equations. Nuclear chemistry is a sub-discipline of chemistry that involves chemical reactions of unstable and radioactive elements, in which both electrons and nuclei may change. The substances that initially participate in the chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by chemical changes, and they produce one or more products, which usually have different properties from the reactants. The reaction usually consists of a series of individual sub-steps, the so-called basic reaction, and information about the precise action process is part of the reaction mechanism. Use chemical equations to describe chemical reactions. The chemical equations symbolically show the starting materials, final products, and sometimes intermediate products and reaction conditions. At a given temperature and chemical concentration, chemical reactions will occur at a specific rate. Generally, the reaction rate increases with increasing temperature because more heat energy can be used to achieve the activation energy required to break the bonds between atoms. The reaction can proceed forward or backward until the reaction is complete or reaches equilibrium. The reaction to reach equilibrium is usually described as spontaneous and can be carried out without any input of free energy. Non-spontaneous reactions require input of free energy to move forward.
