题干

此表是不同温度下水的离子积数据:试回答以下问题:

温度/℃

25

t1

t2

水的离子积常数

1.0×1014

α

1.0×1012

(1)若25<t1<t2,则α____ (填“<”“>”或“=”)1.0×1014,作出此判断的理由是____ 

(2)25℃下,某Na2SO4溶液中c(SO42)=5×104mol•L1,取该溶液1mL,加水稀释至10mL,则稀释后溶液中c(Na+):c(OH)=____ .

(3)t2℃下,将pH=11的苛性钠溶液V1 L与pH=1的稀硫酸V2 L混合(设混合后溶液的体积为原两溶液体积之和),所得混合溶液的pH=2,则V1:V2=____ .

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答案(点此获取答案解析)

>,升高温度,水的电离程度增大,离子积增大,1000:1,9:11

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    Have you ever found yourself in this situation:You hear a song you used to sing when you were a child-a bit of nostalgia(怀旧)or "blast from the past,"as we say.But it is not a distant childhood memory.The words come back to you as clearly as when you sang them all those years ago.

    Researchers at the University of Edinburgh studied the relationship between music and remembering a foreign language.They found that remembering words in a song was the best way to remember even one of the most difficult languages.

    Here is what they did. Researchers took 60 adults and randomly divided them into three groups of 20.Then they gave the groups three different types of "listen-and-repeat" learning conditions.Researchers had one group simply speak the words.They had the second group speak the words to a rhythm,or beat.And they asked the third group to sing the words.

    All three groups studied words from the Hungarian language for 15minutes.Then they took part in a series of language tests to see what they remembered.

    Why Hungarian,you ask ? Researchers said they chose Hungarian because not many people know the language.It does not share any roots with Germanic or Romance languages,such as Italian or Spanish.After the tests were over,the singers came out on top.The people who learned these new Hungarian words by singing them showed a higher overall performance.They did the best in four out of five of the tests.They also performed two times better than those who simply learned the words by speaking them.

    Dr.Katie Overy says singing could lead to new ways to learn a foreign language.The brain likes to remember things when they are contained in a catchy 3,or memorable 4,tune 5.

    Dr.Ludke said the findings could help those who struggle to learn foreign languages.On the University of Edinburgh's website Dr.Ludke writes,"This study provides the first experimental evidence that a listen-and-repeat singing method can support foreign language learning,and opens the door for future research in this area."