14.下列物质中，含碳的质量分数最大的是····························································· [ ]
A．CO B．CH4 C．C2H2 D．CO2
13．某学生使用托盘天平称量固体药品时，将药品放在右盘上，然后在左盘上加了8克砝码，并移动游码到0.8克处，天平达到了平衡，则此药品的重量是············································································ [ ]
A．8.8克 B．7.20克 C．7.2克 D．7.8克
12．除去CO2中混有的少量CO杂质可采用的适宜方法是······································ [ ]
A．点燃混合气体 B．将混合气体通过石灰水
C．将混合气体通过灼热的CuO D．将混合气体通入水中
11．下列叙述中，正确的是··················································································· [ ]
A．二氧化碳分子是由一个碳原子和一个氧分子构成的
B．不同元素的原子其核电荷数一定不同
C．原子是构成物质的最小微粒
D．核外电子数相同的微粒一定属于同种元素
10.将80克KNO3饱和溶液，从60℃降低到20℃。在这个过程中不变的是············· [ ]
A．溶质质量 B．溶剂质量 C．溶解度 D．溶液的质量百分比浓度
9.吸烟有害健康，在公共场所吸烟，会使周围的人被动吸“二手烟”。“二手烟”中含
有一种能与人体血液中血红蛋白结合的有毒气体，该气体是·································· [ ]
A．N2 B．O2 C．CO2 D．CO
8．下列符号中，既表示一个原子，又表示一种元素，还表示一种物质的是··········· [ ]
A．C60 B．2H C．2H2 D．Hg
7．决定元素种类的是原子的················································································· [ ]
A．质子数 B．中子数 C．电子数 D．最外层电子数
6．将面粉、味精、食盐、酒精分别放入水中，不能形成溶液的是························· [ ]
A．面粉 B．味精 C．食盐 D．酒精
5．生活中的下列物质，属于纯净物的是································································ [ ]
A．豆浆 B．酱油 C．糖水 D．蒸馏水