问题 问答题

小刚同学绘制了如图所示A、B两种固体物质的溶解度曲线.

(1)A物质在温度为t2℃时的溶解度是______;温度为t1℃时,A物质与B物质的溶解度是(填“相等”或“不相等”或“不能比较”)______.

(2)溶解度受温度影响变化较小的固体物质,宜采用______的方法结晶.

(3)我国有许多盐碱湖,湖中溶有大量的NaCl和Na2CO3,那里的人们冬天捞碱,夏天晒盐.据此你认为图中(填字母)______曲线与纯碱的溶解度曲线相似.

答案

(1)可从曲线图查出:A物质在温度为t2℃时的溶解度是ag.回答时需要带上单位“g”.

故选Ag;

t1℃时,A物质与B物质的曲线相交,说明此时溶解度相等.

故选:相等;

(2)溶解度受温度影响变化较小的固体物质,采用蒸发溶剂析出晶体的方法结晶.

故答:蒸发溶剂;

(3)从题中“冬天捞碱”可知Na2CO3的溶解度受温度影响较大,温度降低析出纯碱,属冷却结晶,与A相似.

故选A.

阅读理解

Some weight-loss camps, which are rare in China just a few years ago, have sprouted in Beijing, Qingdao, Shenzhen, and other cities. Today about 15 percent of adults, or 200 million Chinese, are reportedly overweight. Of these, 90 million—about 7 percent—are obese(极肥胖的).

Experts say the obesity epidemic is spreading to children, though more slowly than in adults. The trend, they say, will have a huge impact on the health of China’s citizens and economy. “We’re seeing a very large proportion of children and adolescents who are quite heavy and aren’t moving much,” said Barry Popkin, a nutrition professor. Popkin carries out an ongoing health-and-nutrition survey of 16,000 households in China. He says more kids today are overeating and putting on weight “quite quickly.” In just ten years, China’s childhood obesity rate has doubled, with the greatest gains coming in urban areas. “In big cities it’s a big problem.” 

Some experts blame the extra fat on a range of factors, many of them tied to China’s rapidly changing economy and culture. The diets of Chinese adults and children are far higher in calorie-laden meats, fish, eggs, dairy products, fats, and sugars than ever before. In addition, kids—especially city dwellers—are more sedentary today and spend more time indoors in front of homework, television, computer games, and the Internet.

Shuwen Ng, a health economist, says that kids in China now have pocket money, and they spend a portion of it on junk food. Ng adds that advertising and peer groups influence kids’ food choices. Certain foods, such as new candies or fast food, have attractive features.

China’s childhood obesity rate still lags that of the United States, where some 15 percent of kids are said to be obese. But the long-term effects are equally serious.

小题1:According to the passage we know _____.

A.weight-loss camps have been very popular in China six years ago

B.about 290 million Chinese are overweight in China in all

C.in China childhood obesity rate in rural areas is lower than that in major cities

D.America’s childhood obesity rate is lower than China’s小题2: Which of the following is NOT the reason of China’s childhood obesity?

A.Advertising on some new candies

B.High quality diets

C.Playing computer games for long time

D.Having pocket money小题3: The underlined word “sedentary” in the second paragraph probably means _____.

A.attentive

B.earnest

C.absent

D.inactive小题4: According to the passage we can infer _____.

A.obesity explosion in China will affect the United States

B.there is great difference in kids’ food choices now

C.junk food contributes to childhood obesity

D.city children eat more than rural children小题5:What’s the best title for the passage?

A.Chinese Childhood Obesity Explosion

B.Weight-loss Camps in China

C.Obesity Explosion’s Impacts On Chinese Economy

D.Obesity Explosion In China And America

单项选择题