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1.根据氢键的成因可知,H—F…H中的氢键的键能大于H—O…H中氢键的键能,但为什么H_2O的沸点为100℃,而HF的沸点却为20℃呢? 解答依据实验数据,H—F…H中氢键的键能为28kJ/mol,H—O…H氢键的键能为18kJ/mol。但一个水分子当中有两个H—O共价键,它可以形成两个氢键,一个氢键的键能是18kJ/mol,那么两个氢键的键能就是36kJ/mol;而在一个HF分子中,一个氢键的键能是28kJ/mol,液态的水变成气
1. According to the formation of hydrogen bonds, we can see that the hydrogen bond in H-F ... H has a larger bond energy than the hydrogen bond in H-O ... H, but why the boiling point of H 2 O is 100 ℃ and the boiling point of HF is 20 ℃? Answer According to the experimental data, the bond energy of hydrogen bonds in H-F ... H is 28 kJ / mol and the bond energy of H-O ... H hydrogen bonds is 18 kJ / mol. However, there are two H-O covalent bonds in a water molecule, which can form two hydrogen bonds. The bond energy of one hydrogen bond is 18 kJ / mol, and the bond energy of two hydrogen bonds is 36 kJ / mol. In the HF molecule, the bond energy of one hydrogen bond is 28 kJ / mol and the liquid water turns to gas