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问题 选择题

下列事实与结论(或推论)均正确的是(　　)

A．将浓氨水加到盛有AgCl固体的试管中，AgCl固体完全溶解，则所得溶液中c(Ag＋)·c(Cl－)>Ksp(AgCl)

B．物质的量之比为12的Na2O2和NaHCO3的固体混合物，在密闭容器中充分加热反应后，残留的固体是Na2CO3

C．向FeBr2溶液中通入少量的氯气，再向反应后的溶液中滴加KSCN溶液，结果溶液变为红色；那么向FeI2溶液中通入少量的氯气，也会出现同样的现象

D．将某混合气体通入品红溶液中，溶液不褪色，该气体中无Cl2

答案

答案：B

A项，由于氯化银固体溶解，故c(Ag＋)·c(Cl－)＜Ksp(AgCl)；C项，由于还原性Fe2＋大于Br－，而I－的还原性大于Fe2＋，故向FeBr2中通入少量氯气时，先氧化Fe2＋，而向FeI2中通入少量氯气时，先氧化I－，故加入KSCN时，溶液不显血红色；D项，SO2也可以使品红溶液褪色。

点拨：本题考查物质的检验、沉淀溶解平衡，考查考生灵活解决问题的能力。难度中等。

多项选择题

给水系统中气压给水设备主要起（）作用。

A、贮存

B、降压

C、调节水量

D、增压
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What Makes Me the Weight I Am
There’s no easy answer to this question. Your genetic makeup, the physical traits that get passed down to you from your parents, plays a big part in determining your size and weight. (46) But if your parents are smaller than average, you may want to rethink that professional basketball career!
The same goes for your body type. Have you ever heard someone say a person is "big boned" It’s a way of saying the person has a large frame, or skeleton. Big bones usually weigh more than small bones. (47)
Like your height or body type, your genes have a lot to say about what your weight will be. But that’s only part of the story. Being overweight can run in someone’s family, but it may not be because of their genes. (48) And even though some kids gain weight more easily than others, when they eat right and exercise, most kids can be a healthy and happy weight that’s right for them. It’s true — the way you live can change the way you look.
How much you weigh is a balance between the calories you eat and the calories you use. (49) If you spend your free time watching TV, your body won’t use as many calories as it would if you played basketball, skated, or went for a walk. If you are in balance, your weight will stay right for you as you grow. But if you eat more and exercise less, you may become overweight. (50)
A That’s why it’s possible for two kids with the same height, but different weights, to both be the right weight.
B If you eat more calories than your body needs to use, you will gain too much weight.
C Poor eating and exercise habits also run in families and this may be the reason the members of a family are overweight.
D However, many overweight people have difficulty reaching their healthy body weight.
E On file other hand, if you eat less and exercise more, you may lose weight8.
F If both your parents are tall, there is a good chance you’ll be tall.
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