明矾是日常生活中一种常见的盐，可用做净水剂，其化学式为KAl（SO4）2•12H2O，该物质是由 ______种元素组成，其中铝的化合价是 ______．
根据明矾的化学式KAl（SO4）2•12H2O 可知明矾由 K，Al，S，O，H 五种元素组成；
根据在化合物中正负化合价代数和为零，则明矾中铝的化合价为：（+1）+x+（-2）×2=0，
可得x=+3；
故答案为：5；+3．
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| Some one says," time is money." But I think time is 1 important than money. Why? Because when money is spent, we can get it back. however, when time is 2 , It'll never return. That is 3 we must't waste time. It goes without saying that time is usually limited. Even a second is very important. we should make full use of our time to do 4 useful. But it is a pity that there are a lot of people who don't know the important of time. They 5 their limited time smoking, drinking and playing cards. They don't know that wasting time means wasting part of their own 6 . In a word, we should save time. we shouldn't leave today's work for tomorrow, Remember: we have no time to lose. | |||
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