（1）化学用语可准确、简洁地记录、表达和交流化学信息．请用化学用语填空：

①2个氢分子____ 　；           

②构成氯化钠的粒子　____ 　；

③天然气主要成分　____ ；       

④氧化铁中铁元素的化合价____ 　

（2）化学就在我们身边，它与生活息息相关．请回答下列问题：

①____ 　是空气的组成成分之一，可用于食品包装的防腐；

②舞台上出现的云雾缭绕的景象，是使用了____ 升华的缘故．

    “Early to bed, early to rise, makes a man healthy, wealthy(财富) and wise (智慧).”

    This is an old English saying (谚语)．Did you hear of it? It means that we must go to bed early and ____ up early in the morning．Then we will keep ____．We'll also be rich and clever.

    This is true．The body must have ____ sleep to be healthy．Children of young age should have ten ____ sleep every day．Children who don't have enough sleep can't do their work very well．They won't be clever and they may not become rich!

    The body also needs ____．Walking, running, jumping, swimming and playing games are all exercise．Exercise the body strong(强壮).

    Exercise also helps the blood(血) to ____ around inside the body．This is very important．Our blood ____ food to all parts(部分) of our body．The head also needs blood． Exercise helps us to think____.

以下是实验室制取气体常用的化学仪器，请回答下列问题．