问题 问答题

在一个小烧杯里加入20g已研碎成粉末的氢氧化钡晶体,将小烧杯放在事先已滴有3-4滴水的玻璃片上,然后向烧杯内加入约10g氯化铵晶体,并立即用玻璃棒迅速搅拌.一会儿后可观察到玻璃片与小烧杯粘在一起,出现“结冰”现象.试回答下列问题:

(1)如果没有看到“结冰”现象,我们还可以通过哪些方式来说明该反应吸热?(说出两种)______、______;

(2)“结冰”现象说明该反应是一个吸热反应.由此可知反应物的总能量______(填“大于”或“小于”)生成物的总能量.也说明断开旧化学键______(填“吸收”或“放出”)的能量______(填“大于”或“小于”)形成新化学键______(填“吸收”或“放出”)的能量.

答案

(1)氢氧化钡晶体和氯化铵的反应是吸热反应,可以根据用手触摸烧杯外壁看是否变凉、用温度计测混合物的温度看是否降温、玻璃片上结冰现象、烧杯和底部的玻璃片粘在一起等现象来证明,故答案为:用手触摸烧杯外壁看是否变凉;用温度计测混合物的温度看是否降温;

(2)反应是一个吸热反应,则反应物的总能量小于生成物的总能量,旧键断裂吸收的能量高于新键生成释放的能量,故答案为:小于、吸收、大于、放出.

阅读理解

The United Nations says forty million people or so around the world went hungry in 2008, mainly because of higher food prices. Early estimates from the UN Food and Agriculture Organization (FAO) show that 963 million people did not get enough to eat.

World food prices have dropped since early 2008. Prices of major crops have decreased by more than half from their height earlier last year. But they remain high compared to earlier years.

But FAO official Hafez Ghanem says lower prices have failed to end the food crisis (危机) in many poor countries. “For millions in developing countries,” he says, “getting enough food every day to live an active and healthy life is a distant dream. ”

The FAO says food shortage is a threat to people's health. Today, two-thirds of the world's undernourished people live in just a few countries. These are India, the Democratic Republic of Congo, Bangladesh, Indonesia, Pakistan, Ethiopia and so on.

A report on food insecurity warns that the current economic crisis could send even more people into hunger and poverty.

In sub-Saharan Africa, the percentage of the people who continually go hungry fell from 34% in 1997 to 30% in 2008. But the FAO says Ghana is the only country that has reached two sets of hunger reduction targets. These were set by the 1996 World Food Summit and the Millennium Development Goals. The main reason is the growth in agricultural production in Ghana.

The FAO says some countries in Southeast Asia like Thailand and Vietnam have made progress in hunger reduction goals. But South Asia and Central Asia haven't, and North Korea is still in hot water.

小题1:What FAO official Hafez Ghanem says implies(暗示)__________

A.it's easy but takes long to provide people with enough food

B.enough food can make people more active and healthier

C.there is difficulty solving the food shortage in a short time

D.people in developing countries will never get enough food小题2:The underlined word "undernourished" in Para. 4 probably means ________.

A.hungry and unhappy

B.unhealthy for lack of food

C.not fat because of poverty

D.undeveloped and poor小题3:What is the best title of this passage?

A.The food production of the world

B.The hunger reduction target of the FAO

C.The food shortage around the world

D.The solution to the global food shortage

判断题