太阳大气结构从里向外是( )
A:光球-日冕-色球
B:色球-光球-日冕
C:日冕-色球-光球
D:光球-色球-日冕
救命!____!
⑴What's your favourite food ?____ A. Ten yuan.
⑵Where do tigers live ?____ B. They live in the forest.
⑶What's for lunch ? ____ C. I like some noodles.
⑷How much is it ?____ D. My favourite food is rice.
⑸Can you swim ?____ E. No, I can't.
填空
9 + ____ = 12 ____ + 5=18 4+ ____ =12
7+ ____ =15 5+ ____ =12 8+ ____ =16
药品名称
熔点/℃
沸点(℃)
密度g/cm3
溶解性
丁醇
﹣89.5
117.7
0.8098
微溶于水、溶于浓硫酸
1﹣溴丁烷
﹣112.4
101.6
1.2760
不溶于水和浓硫酸
根据题意完成填空:
(一)制备1﹣溴丁烷粗产品:在下图装置的圆底烧瓶中依次加入NaBr,10mL正丁醇,2粒沸石,分批加入1:1的硫酸溶液,摇匀,加热30min.化学方程式:NaBr+H2SO4+CH3CH2CH2CH2OH→CH3CH2CH2CH2Br+NaHSO4+H2O