几道高一题

1.--why does she feel so unhappy?
--___what she has just so heard.
A.Because of B.Since C.As D.Because
2.--Tom insisted that he ___not wrong and ___punished.
A.is;can't B.was;not be C.was;wasn't D.was;couldn't be
3.--He made anothe wonderful discovery ____of great importance to science.
A.which Ithink is B.which Ithink is C.I think it is D.I think which is
4.--It was on the farm ___his parents ever worked ____he fell in love with a girl from America.
A.that;where B.where;which C.where ;that D.that;that
5.下列物质中,能够导电的电解质是___
A,酒精 B.氯化钙晶体 C 氯化钠溶液 D.熔融的氧化镁
6.过滤后食盐水仍含有可溶的CaCl2,MgCl2,NaSO4等杂质,通过如下几个实验步骤,可制得纯净的食盐水:1加入稍过量的碳酸钠溶液;2.加入稍过量的氢氧化钠溶液;3.加入稍过量的氯化钡溶液;4.滴入稀盐酸至无气泡产生;5.过滤.正确的操作步骤是____
A.32154 B.12354 C.23145 D.35214
7.一定量的液态化合物XY2,在一定量的氧气中恰好完全燃烧,生成气体XO2和YO2.反应方程式为XY2(液)+3 O2=点燃=XO2+2Y2,冷却后,在标准状况下测得生成的气体体积是672ML,则
1.反应前氧气的体积是___ML
2.化合物XY2的摩尔质量是____
3.若XY2的分子中两元素的质量比是3:16