一有机物分子组成中氢原子数的规律由C、H或C、H、O组成的有机物中,氢原子数必为偶数;含C、H、O、X(X为卤原子)的有机物中,H与X的原子数之和为偶数。此规律常用在解答根据结构式书写化学式的题型中。二各类烃分子结构中氢原子数增减的规律与等碳原子数的烷烃中氢原子个数相比,分子中每少2个H相当于形成1个C=C或C=O或形成一个碳环;少4 The organic matter composed of C, H or C, H, O, the number of hydrogen atoms must be an even number; Organic matter containing C, H, O, X (X is a halogen atom) The sum of the atomic numbers of H and X is an even number. This rule is commonly used in answering questions based on structured writing chemistry. Two kinds of hydrocarbon molecular structure of the number of hydrogen atoms increase and decrease of the law and the number of carbon atoms in the number of hydrogen atoms in the hydrocarbon compared to the number of each 2 H H is equivalent to the formation of a C = C or C = O or formation A carbon ring; less 4