题目

（2011年河北，36题）已知氯化钠溶液和硝酸银溶液反应生成氯化银(AgCl)沉淀和硝酸钠。为测定某生理盐水的溶质质量分数，将生理盐水样品与足量的硝酸银溶液混合，有关实验数据如下表：(1)反应后生成氯化银的质量为g(2)计算该生理盐水的溶质质量分数。  答案：(1)2.87    (2)解：设1 3 0 g生理盐水中含NaCl的质量为x。    NaCl+AgN03=AgCl占一~-NaN03    5 8.5   1435、    x    2．87 g    生理盐水中Nacl的质量分数为答：该生理盐水中NaCl的质量分数0．9％。解析:略 阅读理解。1. Which of the following is discouraged by the Friends organization? A. To build massive complexes for public amusement. B. To prevent possible damages to the National Park. C. To help protect and improve the Park for all to enjoy. D. To sponsor publicationsand projects in local school. 2. One of thebenefits for members of Friends is to _____. A. have Friends' goods free of charge B. visit any place not open to the public C. take part in work parties if they want toD. give talks in their fields on current issues 3. The purpose of this poster is to invite more people to _____. A. raise money for the Friends organization B. join the Friends organization and be members of it C. work as managers for Pembroke shire National Park D. enjoy the landscape of Pembroke shire National Park