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化合价升降法配平氧化还原反应方程式的关键在于具体物质中元素化合价的标定及化合价升降总数的计算.本文根据不同反应采用五种不同的标价方法,能达到快速配平的目的.一、定零标价法用常规方法确定化合物中元素化合价有困难时,可将该化合物中各元素都标为零价.例1.Fe_3P+HNO_3——Fe(NO_3)_3+NO+H_3PO_4+H_2O将Fe_3P中的铁和磷元素的化合价都定为零价,则元素化合价升降关系为:Fe 0→+3 升高 3×3 P 0→+5 升高5 共升高14|×3,N +5→+2 降低3 共降低3|×14,可配得:3Fe_3P+41HNO_3=9Fe(NO_3)_3+14NO+3H_3PO_4+16H_2O.二、平均标价法当同一反应物中的同种元素的原子出现两次时,可将它们同等对待,根据化合物中化合价代数和等于零的原则予以平均标价.若方程式中出现双原子分子时,有关原子个数要扩大2倍.例2.NH_4NO_3——N_2+HNO_3+H_2O,
The key to balancing the redox reaction equation with the valence-valence method is the calibration of elemental valences and the calculation of the total number of valences in specific materials. This paper uses five different pricing methods based on different reactions to achieve the purpose of quick balancing. First, the zero-fixing method When it is difficult to determine the elemental valence in a compound by conventional methods, each element in the compound can be marked as zero. Example 1. Fe_3P+HNO_3—Fe(NO_3)_3+NO+H_3PO_4+H_2O The iron in Fe_3P The valence of phosphorous elements is all set to zero, then the elemental valences rise and fall as follows: Fe 0 → +3 increases 3 × 3 P 0 → +5 increases 5 increases 14 | × 3, and N +5 → + 2 decreases 3 total reduction of 3 | × 14, can be worth: 3Fe_3P + 41HNO_3 = 9Fe (NO_3)_3 + 14NO + 3H_3PO_4 + 16H_2O. Second, the average price of the same reaction when the atoms of the same element appear twice, you can Treat them equally, according to the compound valence algebra and the principle of equal to zero to be the average price. If there are diatomic molecules in the equation, the number of related atoms to be expanded by 2 times. Example 2. NH_4NO_3 - N_2+HNO_3+H_2O,