问题 填空题

下列物质中:①NaCl ②Na2O ③CH3COOH ④CO2  ⑤NaHCO3 ⑥NH3•H2O ⑦Fe ⑧金刚石 ⑨Cl2 ⑩澄清石灰水⑪NaOH  属于强电解质的有______;属于弱电解质的有:______.(填序号)

答案

①NaCl是盐,属于强电解质;

②Na2O是金属氧化物,属于强电解质;

③CH3COOH是弱酸,属于弱电解质;

④CO2 是非电解质;

 ⑤NaHCO3是盐,属于强电解质;

⑥NH3•H2O是弱碱,属于弱电解质;

⑦Fe、⑧金刚石、⑨Cl2 都是单质,既不是电解质也不是非电解质;

⑩澄清石灰水属于混合物,既不是电解质也不是非电解质;

⑪NaOH 是强碱,是强电解质.

故答案为 ①②⑤⑪;③⑥.

单项选择题

Like many of my generation, I have a weakness for hero worship. At some point, however, we all to question our heroes and our need for them. This leads us to ask: What is a hero

Despite immense differences in cultures, heroes around the world generally share a number of characteristics that instruct and inspire people.

A hero does something worth talking about. A hero has a story of adventure to tell and community who will listen. But a hero goes beyond mere fame.

Heroes serve powers or principles larger than themselves. Like high-voltage transformers, heroes take the energy of higher powers and step it down so that it can be used by ordinary people.

The hero lives a life worthy of imitation. Those who imitate a genuine hero experience life with new depth, enthusiasm, and meaning. A sure test for would-be heroes is what or whom do they serve What are they willing to live and die for The answer or evidence suggests they serve only their own fame, they may be famous persons but not heroes. Madonna and Michael Jackson are famous, but who would claim that their fans find life more abundant

Heroes are catalysts (催化剂) for change. They have a vision from the mountaintop. They have the skill and the charm to move the masses. They create new possibilities. Without Gandhi, India might still be part of the British Empire. Without Rosa Parks and Martin Luther King, Jr., we might still have segregated (隔离的) buses, restaurants, and parks. It may be possible for largescale change to occur without leaders with magnetic personalities, but the pace of change would be slow, the vision uncertain, and the committee meetings endless.

Gandhi and Martin Luther King are typical examples of outstanding leaders who ().

A. are good at demonstrating their charming characters

B. can move the masses with their forceful speeches

C. are capable of meeting all challenges and hardships

D. can provide an answer to the problems of their people

单项选择题