【简答题】氢气是未来最理想的能源,科学家最近研制出利用太阳能产生激光,并在二氧化钛(TiO 2 )表面作用使海水分解得到氢气的新技术:2H 2 O 2H 2 ↑+O 2 ↑。制得的氢气可用于燃料电池。试回答下列问题 (1)水分解时,断裂的化学键为________键(填离子或共价),分解海水的反应属于________反应(填放热或吸热)。 (2 )某种氢氧燃料电池是用固体金属化物陶瓷作电解质,两极上发生的电极...
【单选题】The United Kingdomis the______most populous country, with an estimated 66 million inhabitants in 2017.
【单选题】--- Both Li Lei and Han Meimei _______ fond of the TV program A Bite of China. ---- I am also deeply moved by its stories.
【简答题】农田、园林的喷灌装置一边喷水一边旋转,这是因为喷口的朝向稍有偏斜,水从喷口喷出时,弯管因反冲而旋转,这样可以自动改变喷水的方向。这里运用了 。(选填“动量守恒定理”或“动能定理”)
【单选题】Not only I but also Li Lei and Han Meimei ________ tired of so much homework every day. [ ]
【单选题】The report written by the marketing department showed that overall prices are up 7.5%_____the previous quarter.