题目

Warren Harding was the 29th President of the United States, serving from 1921 until his death in 1923.   56   One was a successful international conference (会议). After World War One, Britain, Japan and the United States expanded their navies (海军). They built bigger and bigger ships. Many members of the United States Congress worried about the cost.   57   They asked President Harding to organize a conference to discuss these issues.  58   President Harding invited representatives from the major naval powers of the time  Britain, Japan, France and Italy. He also invit实验室配制一定物质的量浓度的溶液，需经计算、称量、溶解、移液、洗涤、定容、摇匀、装瓶等步骤．现需配制0.2mol/L的CuSO4溶液500mL．回答下列问题：（1）用托盘天平称取CuSO4?5H2O晶体的质量是 g．（2）将溶解并冷却后的溶液转移的过程中用到的玻璃仪器有 ．（3）定容时，加水至距刻度线1-2cm时改用胶头滴管滴加蒸馏水至 ．（4）下列情况会使所配溶液浓度偏低的是 ．（填序号）A．定容时俯视B．未将洗涤烧杯后的溶液转移至容量瓶C．加蒸馏水时，不慎超过了刻度线D．砝码上沾有杂质（或者使用生锈的砝码）E．容量瓶使用前未经干燥．