听下面一段较长对话,回答以下小题。 (1) Where does the conversation take place? A . In an office. B . In the street. C . On the subway. (2) What's the relationship between the two speakers? A . Colleagues. B . Strangers. C . Roommates. (3) What are the two speakers mainly talking about? A . High price of gas. B . Importance of exercise. C . Advantages of taking the subway.
某课外活动小组收集了一种合金进行研究.
(1)外观暗灰色,表皮光滑.
(2)在酒精灯上灼烧,火焰呈绿色;合金片熔化,但不滴落.
(3)取刮去表皮的金属10.0 g,放入足量H2SO4中,收集到标准状况下的H2 9.96 L.
(4)另取刮去表皮的金属10.0 g,放入足量NaOH(aq)中,也收集到标准状况下的H2 9.96 L.
试据此判断,合金中一定含有的元素是________(写元素符号);下列元素可能含有的是________(填选项编号).
A.Ag
B.Mg
C.Na
D.Fe
如果该合金中只含两种元素,它们的质量比是________.