题目

My (father) birthday is on October the fifth. 答案：【1】father's不定项室温下一密闭容器里混有某气态烃和适量氧气，点火使之充分燃烧，再冷却至室温，容器中的压强变为反应前的0.5倍，此气态烃是A．乙烷 B．丙烷C．丁烷D．乙烯