covalent bonding 問題.....

In chemistry, there are two kinds of stabilities involved. The first one
is kinetically stable related to the activation energy involved when a cpd
is formed while the other is energetically stable related to the amount
of energy will be released during the reaction . The more energy released,
the less stable it is. It is necessary to overcome the activation energy before
forming a new cpd or starting the reaction, however. 在這方面氫氣是穩定的, 因為不會自我燃燒比white phosphorus為穩定,但是white phosphorus在氧氣充足時則會燃燒,形成P4O10

In order to make hydrogen have a reaction, the high activation enery
must be overcome. In this approach, if you don’t apply any energy to
hydrogen such as ignition, hydrogen will not burn. The hydrogen is
said to be kinetically stable.

However, once ignition(點燃) is employed, it burns in oxygen to give water.
The reaction is exothermic (ie energy is given out). In this manner, the
hydrogen is said to be energetically unstable due to a more negative
energy result. (ΔH < 0) 原先氫的能量(ΔHf = 0)是零,與氧反應後,給出一個負的能量,因為有bond formation 之故,由於是放熱反應,現在水中的氫原子比起在氫氣中的氫原子為穩定. 從這方面來看的話,氫氣是
energetically unstable的

這也解釋了為何氫氣加氧氣在沒有點火的情況下是不會反應的,因為
kinetically stable,即是有高的活化能(activation energ)之故

所以stable還是reactive呢??要從不同角度看的.

問一問你的化學老師石墨穩定還是鑽石比較穩定?答案是石墨,但是為何鑽石又不會轉化為石墨呢?

cpd = compound