一、定“1”法所谓定“1”法，就是找出反应式中较复杂的化学式，假定其系数为1，再根据这种化学式的原子个数，按顺序确定其他化学式的系数。如果系数中出现分数，须通分，再去分母。配平的原则是先配化合物，最后配单质；配平关键是定哪一个化学式的系数为1；配平要领是掌握 First, set “1” method The so-called “1” method, is to find out more complex chemical formula in the reaction, assuming that the coefficient is 1, according to the number of atoms of this formula, according to the order to determine the coefficient of other chemical formula. If there is a score in the coefficient, it must pass through and then denominator. The principle of trimming is to mix the compound first, and finally to match the element; the key to the trim is to determine which chemical formula has a coefficient of 1;