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一、假设1法例1.1924年,我国药物学家从中药麻黄中提取出了麻黄素,并证明麻黄素具有平喘作用。将10g麻黄素完全燃烧可得26.67gCO_2和8.18gH_2O,测得麻黄素中含氮8.48%,它的实验式为C_xH_yN_zO_w,它的分子式为( )。A.C_10H_15NO B.C_20H_30NOC.C_10H_l5N_2O_3 D.C_20H_30N_2O解析:当有机物的元素组成较多时,可先假设其中原子个数可能最少的元素的原子个数为1。N、S、卤素等元素的原子个数相对较少。因此该题可假设麻黄素
I. Hypothesis 1.1.1 In the year of 1.1924, Chinese pharmacologists extracted ephedrine from traditional Chinese medicine Ephedra, and proved that ephedrine has antiasthmatic effects. The complete combustion of 10 g of ephedrine yielded 26.67 g of CO2 and 8.18 g of H2O. The measured nitrogen content of ephedrine was 8.48%. Its empirical formula was C_xH_yN_zO_w and its molecular formula was (). A.C_10H_15NO B.C_20H_30NOC.C_10H_l5N_2O_3 D.C_20H_30N_2O Analysis: When there are many elements in an organic matter, it is assumed that the number of atoms of the element whose number of atoms may be the least is 1 . The number of atoms such as N, S, and halogen is relatively small. Therefore, the problem can be assumed to be ephedrine.