某核素_Z^AX的氯化物XCl₂  1.11g配成溶液后，需用1mol/L的硝酸银溶液20mL才能把氯离子完全沉淀下来，则

（1）X的质量数为 ____　

（2）若X的核内中子数为20，55.5g XCl₂中所含质子的物质的量为 ____　mol．

从右栏选项中找出左栏各句的恰当应答。

                I                                                                                                   II

46. 1.Hello,Jenny speaking. ____                                             A.I like music that I can dance to.
47. 2.How often does Jeff go to the library? ____                   B. It's 876-9548.
    
48. 3.What's your telephone number?    ____                         C. They're pretty good.
    
49. 4.What do you think of the cartoons? ____                       D. Hi, Jenny. It's Steve.
    
50. 5.What kind of music do you like?  ____                            E. Hi, I'm Jack.
    

                                                                                                   F. Once a week.