题目

某氯化镁溶液的密度为1.18 g·cm－3，其中镁离子的质量分数为5.1%,300 mL该溶液中Cl－的物质的量约为( ) A．0.37 mol          B．0.63 mol C．0.74 mol                       D．1.5 mol 答案：解析：选D 由物质的量浓度和质量分数的换算关系式可知：c(Mg2＋)＝＝ ≈ 2．51 mol·L－1，所以n(MgCl2)＝2.51 mol·L－1×0.3 L≈0.75 mol，n(Cl－)＝0.75 mol×2＝1.5 mol。阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中的词语的正确形式填空。COME AND EAT HERE Wang peng felt very 小题1: （frustrate）when he saw none of his patrons(常客) would eat in his restaurant. In his opinion, nothing could be better than his fried rice, mutton kebabs, fatty pork or his   小题2: (sugar) cola. Who won his customers? He followed one of his best friends 小题3: Yong Hui’s newly   小题4:(open) slimming restaurant and was 小题5: (amaze) at the menu there: raw vegetables, fruit and water. It was obvious that Yong Hui was telling lies when promising to make the customers thinner. In order to win his customers back, he went to the library  小题6: (do) some research, 小题7: showed Yong Hui’s menu didn’t give the customers energy-giving food. Having found out the weakness of Yong Hui’s menu, Wang Peng 小题8:(write)his own sign, 小题9: (say) energy-giving food served. In fact, there was weakness in his menu, too. Food at his restaurant contains too much fat. So the only solution is to combine the two menus together to be a    小题10:  (balance) menu.