一、根据质量守恒定律推断物质的组成[例1]酒精在空气中燃烧生成二氧化碳和水,由此可推断酒精的成分定含有_____和______元素,可能含有______元素。[解析]酒精燃烧是跟空气中的氧气反应生成CO2和H2O,根据质量守定律可知,化学反应前后元素的种类不变,可证明酒精的成分里一定含碳 I. Inferring the composition of substances based on the law of conservation of mass [Example 1] Alcohol is burned in the air to produce carbon dioxide and water, from which it can be inferred that the composition of alcohol contains _____ and ______ elements, which may contain ______ elements. [Analysis] Alcohol combustion reacts with oxygen in the air to produce CO2 and H2O. According to the law of quality assurance, the types of elements before and after the chemical reaction do not change, and it can be proved that the composition of alcohol must contain carbon.