In Chemistry, What Is a Limiting Reactant?
In chemical reactions, the substances that can participate in the reaction are called reactants, which refer to the substances that can be consumed in a certain chemical reaction. Solvents and catalysts involved in chemical reactions are not counted as reactants.
- in
- A reaction in which the product can continue to react with an excess of reactants
- Example 1. CO 2 is passed into an excess of NaOH solution: CO 2 + 2OH-= CO 3 2- + H 2 O
- Excess CO2 is passed into the NaOH solution: CO 2 + OH-= HCO 3-
- Example 2: A small amount of NaOH solution was dropped into the AlCl3 solution to react: Al 3+ + 3OH = Al (OH) 3
- A small amount of AlCl 3 solution is dropped into NaOH solution to react: Al 3+ + 4OH == AlO 2 + 2H 2 O
- Example 3. Reaction of FeCl 3 solution with Na 2 S solution
- Fe 3+ and S 2 can occur
- The reactivity of the same substance in different structural states varies greatly.
- The more complete the structure of the reactants, the fewer defects of character, which is not conducive to diffusion, and the solid-phase reaction speed is slow. The bond between particles is strong, the structure is firm, the character is high, and the reactivity is low.
- Polycrystalline transformation process is often accompanied by lattice rearrangement, which makes the lattice loose and activated. For example, SiO 2 polycrystalline transformation can make the lattice loose and activated, and it is easy to break.
- Thermal decomposition and dehydration, because the gas and vapor are exhausted from the crystal, make the crystal lattice have a larger specific surface area and lattice defects, or become an amorphous substance after decomposition and dehydration, which increases the reaction activity and accelerates the progress of the solid phase reaction. For example, lightly burned raw materials have much higher reactivity than dead burned raw materials. In the case of light burning, CaCO 3 is decomposed to obtain loose and porous CaO, which is beneficial for it to react with SiO 2 to generate C 2 S. Kaolinite Al 2 O 3 · 2SiO 2 · 2H 2 O is heated and dehydrated to obtain metakaolinite Al 2 O 3 · 2SiO 2 , and heating is continued to obtain Al 2 O 3 and SiO 2 with certain activity. [1]