解题要点:Standard enthalpy change of atomisation的定义: The enthalpy change when one mole of gaseous atoms is formed from the element in its standard state under standard conditions. 通过重点划出来的两个要点来判断答案。 产物系数一定是1,代表1mol 产物状态只能是g 箭头左边物质要符合在standard condition下的状态 答案:B