——Zhou Yang won the 1500-meter Olympic title at the Sochi Winter Games on February 15.——_______________________.
A:I like swimming best
B:That's all right
C:Good luck
D:That's great
某核素ZAX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.
下列句中加线的成语使用不恰当的一项是( )
—People now can know what is happening in the world quickly. —You're right.With the help of computers,news can ___every corner of the world.
人体中二氧化碳浓度最高的地方是( )