Substrate is participation biochemical reaction A substance that can be a chemical element, molecule or compound and can form a product by acting on it. The substrate of one biochemical reaction is often also the product of another chemical reaction. [1] Influence of substrate amount on reaction results
Chemical reaction is an important part of chemistry learning. The chemical reactions between substances are often complex and varied. Many chemical reactions need to take place under certain conditions. Without reaction conditions, some reactions cannot take place or go on slowly. The amount of reactants has influence on the reaction results.
1、CO two Gas flows into NaOH solution. When n CO two /When n NaOH ≤ 1/2, the reaction equation is CO two + 2NaOH== Na two CO three +H two O； When n CO two /When n NaOH ≥ 1/1, the reaction equation is CO two + NaOH==NaHCO three 。 Similar: SO two 、CO two 、 H two Gas such as S enters Ca (OH) two 、 Ba(OH) two , KOH, NaOH, etc.
2. NaOH and H three PO four Neutralization reaction of. When n NaOH/n H three PO four ==1: 1, the reaction equation is NaOH+H three PO four ==NaH two PO four +H two O； When n NaOH/n H three PO four ==2: 1, the reaction equation is 2NaOH+H three PO four ==Na two HPO four +2H two O； When n NaOH/n H three PO four ==3: 1, the reaction equation is 3NaOH+H three PO four ==Na three PO four +3H two O。 Similar: KOH and H three PO four 、H two SO four Reaction.
3、Cl two And FeBr two Reaction of solution. When n Cl two /n FeBr two ==1/2 (insufficient chlorine), the reaction equation is 3Cl two +6 FeBr two ==2FeCl three +4FeBr three ； When nCl two /nFeBr two ==3/2 (excess chlorine), the reaction equation is 3Cl two +2 FeBr two ==2FeCl three +2Br two 。
4. To FeCl three Add Na to the solution two S。 When n Na two S / n FeCl three ≤1/2（Na two When S is insufficient), the reaction equation is Na two S +2 FeCl three ==S↓+2NaCl+2FeCl two ； When n Na two S / n FeCl three ≥3/2（FeCl three When insufficient), the reaction equation is 3Na two S+ 2 FeCl three ==S↓+6NaCl+2FeS↓。
5. Fe reacts with dilute nitric acid. When n Fe/nHNO three When ≤ 1/4 (Fe is insufficient), the reaction equation is Fe+4HNO three (dilute)==Fe (NO3) three +NO↑+2H two O； When n Fe/nHNO three When ≥ 3/8 (excessive Fe), the reaction equation is 3Fe+8HNO three (dilute)==3Fe (NO three ) two +2NO↑+4H two O。
6. P reacts with chlorine. When n P/n Cl two ≥2/3 （Cl two When insufficient), the reaction equation is 2P+3Cl two ==2PCl three ； When n P/n Cl two When ≤ 2/5 (P insufficient), the reaction equation is 2P+5 Cl two ==2PCl five 。
7、H two S combustion in oxygen. When n H two S / n O two ≥2/1 （H two S excess), the reaction equation is 2H two S+O two
==2S+2H two O； When n H two S / n O two ≤2/3 （O two Excess), the reaction equation is 2 H two S+3O two ==2SO two +2H two O。
8. To NaAlO two CO is introduced into the solution two 。 When n CO two / n NaAlO two ≤1/2（CO two When insufficient), the reaction equation is CO two + 2NaAlO two +3H two O== Na two CO three +2Al(OH) three ↓； When n CO two / n NaAlO two ≥1/1（CO two Excess), the reaction equation is CO two + NaAlO two +2H two O== NaHCO three +Al(OH) three ↓。 Similar: CO two Feed Na two SiO three 、 Ca(ClO) two In the solution of.
9. To NaAlO two Add dilute hydrochloric acid (or strong acids such as sulfuric acid or nitric acid) to the solution. When n HCl/n NaAlO two ≤ 1 (insufficient HCl), reaction Ionic equation Is AlO two -- +H + + H two O== Al(OH) three ↓； When n HCl/n NaAlO two When ≥ 4/1 (HCl excess), the reaction ion equation is AlO two -- +4H + == Al three + +2H two O。 10. To AlCl three Add NaOH solution or KOH and other strong alkaline solutions into the solution. When nNaOH/nAlCl three When ≤ 3/1, the reaction ion equation is Al three + +3OH -- == Al(OH) three ↓； When nNaOH/nAlCl three When ≥ 4/1, the reaction ion equation is Al 3+ +4OH -- == AlO two -- +2H two O。
11. Zinc powder and FeCl three Solution reaction. When n Zn/n FeCl three ≤1/2（FeCl three When sufficient), the reaction equation is Zn+2 FeCl three == ZnCl two +2 FeCl two ； When n Zn/n FeCl three When ≥ 3/2 (sufficient Zn), the reaction equation is 3Zn+2 FeCl three == 3ZnCl two +2 Fe。
12. Coke reacts with quartz at high temperature. When nC/nSiO two When ≤ 2/1, the reaction equation is 2C+SiO two ==Si+2CO↑； When nC/nSiO two When ≥ 3/1, the reaction equation is 3C+SiO two ==SiC+2CO↑；
13. Alum and Barium hydroxide Reaction. When n Ba (OH) two /n KAl(SO four ) two ·12H two When O=2/3, the reaction equation is 2KAl (SO four ) two ·12H two O+ 3Ba(OH) two ==2BaSO four ↓+2Al(OH) three ↓+K two SO four +12H two O； When n Ba (OH) two /n KAl(SO four ) two ·12H two When O=2/1, the reaction equation is KAl (SO four ) two ·12H two O+ 2Ba(OH) two ==2BaSO four ↓+KAlO two +14H two O。 14. Alkynes and H two Or halogen. When n alkynes/n H two When ≥ 1/1, the reaction equation is RC ∨ CR '+H two → RCH==CHR‘； N Alkynes/n H two When ≤ 1/2, the reaction equation is RC ∨ CR '+2H two →RCH two ―CH two R’。 [2]
Effect of substrate amount on conversion rate
At constant temperature and pressure:
If the reaction mA (g)+nB (g) ≈ pC (g)+qD (g)
(1) When the amount of reactants is not changed and the equilibrium moves forward due to the change of temperature or pressure, the conversion of each reactant increases;
(2) If the reaction reaches equilibrium and the amount of one gaseous reactant is increased, the conversion rate of the other reactant increases, but the conversion rate of itself decreases;
(3) Feed ratio equal to gaseous reactant Stoichiometric number The conversion rate of each reactant is equal. At constant temperature and volume:
1、 There is only one reactant, such reaction is: aA (g) ≈ bB (g)+cC (g)
Under the condition of constant temperature and constant volume, after the above reversible reaction reaches the chemical equilibrium state, increase the amount of A, that is, increase the concentration of reactants. according to Le Chatelier's principle , the equilibrium moves towards the positive reaction direction, but the change of the conversion rate of reactant A is related to the metered number of gaseous substances: (1) If a=b+c, the conversion rate of A remains unchanged; (2) If a>b+c, the conversion rate of A increases; (3) If a 2、 More than one reactant
Such reaction is: aA (g)+bB (g) ≈ cC (g)+dD (g)
1. If only the amount of A is increased, the balance moves forward, and the conversion rate of B increases, while the conversion rate of A decreases. 2. If the amount of reactants A and B is increased by the same multiple as the original proportion, the balance moves to the positive reaction direction, and the conversion rate of reactants is Chemical equation The metered number of the gas substance in is related to: (1) If a+b=c+d, the conversion rates of A and B are unchanged; (2) If a+b>c+d, both A and B conversion rates increase; (3) If a+b [2] 
