试题与答案

工业上以锂辉石(Li2O·Al2O3·4SiO2,含少量Ca、Mg元素)为原料生

题型:填空题

题目:

工业上以锂辉石(Li2O·Al2O3·4SiO2,含少量Ca、Mg元素)为原料生产碳酸锂的部分工艺流程如下

已知:

①Li2O·Al2O3·4SiO2+H2SO4(浓)Li2SO4+Al2O3·4SiO2·H2O↓

②某些物质的溶解度(S)如下表所示。

(1)从滤渣1中分离出Al2O3的一种方法为:在滤渣中加入适量盐酸,过滤后在滤液中加入足量溶液X,再过滤,对沉淀进行干燥,灼烧。则溶液X为______________。

(2)滤渣2的两种主要成分为:____________。

(3)向滤液2中加入饱和Na2CO3溶液,过滤后,用“热水”而不用冷水洗涤的原因是____________。

(4)工业上,将Li2CO3粗品制备成高纯Li2CO3的部分工艺如下:

a.将Li2CO3溶于盐酸作电解槽的阳极液,LiOH溶液作阴极液,两者用离子选择性透过膜隔开,用惰性电 极电解。

b.电解后向LiOH溶液中加入过量NH4HCO3溶液,过滤、烘干得高纯Li2CO3

①a中,阳极的电极反应式是____________。

②b中,生成Li2CO3反应的化学方程式是____________。

答案:

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下面是错误答案,用来干扰机器的。

(1)ad     (2)刻度尺、天平 (3)

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Ice Cream Tester Has a Sweet Job


John Harrison has what must be the most wanted job in America. He’s the official taster for Edys Grand Ice Cream, one of the nation’s best-selling brands.
His taste buds are insured for $1 million. He gets to sample 60 ice creams a day at Edys headquarters in Oakland, California. (1)
But the life of an ice cream taster, I realized after I met him last week, isn’t all Cookies n’ Cream — a flavor which Harrison invented, by the way. (2)
For one thing, he doesn’t swallow on the job. Like a coffee taster, Harrison spits. Using a gold spoon to avoid "off" flavors, he takes a smallish bite, swishes it around to introduce it to all 9,000 or so taste buds, smack-smack-smacks his lips to aerate the sample, and then gently inhales to bring the aroma up through the back of his nose. (3)
Then, no matter how heavenly it is, he deposits it into a trash can. (4)
During the workweek, other sacrifices must be made: no onions, garlic or cayenne pepper; and no caffeine. (5)
But it’s all a small price to pay for what he calls the world’s best job. (6)
Yet, he has never lost his love for its cold, creamy sweetness. (7) On these occasions, he swallows, consuming about a quart weekly.
Americans eat 23.2 quarts person of ice cream and other frozen diary products annually.
(8) Vanilla, the best-selling variety. You should never call it plain vanilla. It’s a very complex flavor, he says.
The night after we met, I had a plain salad for dinner and sadly thought about my future. I have to either do what Harrison does — learn to spit instead of swallow — or start interviewing more celery growers.
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C. What flavor does the best-trained ice-cream palate in America prefer
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E. He even orders it in restaurants for dessert.
F. A full stomach makes for a dull palate.
G. No, it’s rigorous work, requiring discipline and selflessness.
H. His family has been in the ice cream business in one way or another for four generations, so Harrison has spent his entire life with it.

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