问题 填空题

人类的生产和生活都离不开金属材料.

(1)铁锅是有益于人类健康的理想炊具,但它很容易跟水和      等发生反应而生锈.写出一种预防你家铁锅生锈的具体做法                    

(2)小倩做了如图实验(铁片和镁片的形状和大小相同).请回答:

①小倩根据“甲中产生气泡比乙中快”得出镁的金属活动性比铁     (填“强”或“弱”).

②完全反应后,过滤,把滤液都倒进同一个烧杯中,加入过量的锌,待充分反应后再过滤,得到的固体中一定含有的物质是      ;得到溶液的质量       (选填“大于”、“小于”或“等于”)与锌反应前溶液的质量.

答案

(1)氧气;保持铁锅洁净、干燥   (2)①强     ②铁和锌;大于

题目分析:(1)铁生锈实际是铁与空气中的氧气和水分发生化学反应;控制铁生锈的条件可防止铁锅生锈,隔绝空气或水分可防止铁锅生锈,如保持铁锅洁净、干燥;

故答案为:氧气;保持铁锅洁净、干燥;

(2)①“甲中产生气泡比乙中快”说明镁的金属活动性比铁强,故答案为:强;

②锌比铁活泼,不如镁活泼,因此加入过量的锌,锌会置换出硫酸亚铁中铁,因为锌过量,所以待充分反应后再过滤,得到的固体中一定含有的物质是铁和锌;锌与硫酸亚铁反应生成硫酸锌和铁,反应的化学方程式为:Zn+FeSO4=ZnSO4+Fe,65克的锌与152克的硫酸亚铁反应生成56克的铁,同时生成161克的硫酸锌,故反应后溶液的质量增加;

故答案为:铁和锌;大于.

点评:本题难度不大,掌握铁生锈的条件和防止铁生锈的方法以及金属的活动性的有关知识是解题的关键,属于基础知识的考查.

阅读理解

阅读理解。

     Three types of pangolins (穿山甲) exist in Africa - the giant pangolin, the tree pangolin and the most

widespread, the ground pangolin. Pangolins have small heads and long, broad tails. They are toothless and

have no external ears, although their hearing is good. Their sense of smell is well-developed, but their sight

is poor. The weight of the scales (鳞片) and skin make up about 20% of their weight.

     The common pangolin prefers sandy soils and is found in woodlands and savannas (热带草原), within

reach of water.

     All pangolins can roll themselves into a ball to defend themselves. The cutting action of their scales protects

them too. Pangolins also have scent glands (臭腺) that release strong, foul smelling secretions. Pangolins are

normally alone. Females are usually alone with their young. The young are 6 inches long and weigh 12 ounces

at birth. Their pale, soft scales begin to harden by the second day. The baby is folded in the mother's lap or

rolled-up body. It is nursed for 3 to 4 months and begins to eat termites (白蚁) at 1 month. At this time the

infant begins to accompany the mother, perhaps riding on the base of her tail. If the mother senses danger the

baby slips under her and is protected when she rolls up her body.

     Pangolins use their sense of smell to locate termite and ant nests. They dig up the insects with their claws

and use their extremely long tongues to eat them.

1. When pangolins are ____, they release strong, foul smelling secretions.

A. happy

B. sad

C. frightened

D. angry

2. Which of the following words best describes the function of the pangolin's scales? 

A. Heavy.

B. Beautiful.

C. Protective.

D. Hard.

3. When does the infant begin to accompany the mother pangolin?

A. At l month old.

B. At 2 months old.

C. At 2-3 months old.

D. At 3-4 months old.

4. What does the last paragraph mainly talk about?

A. The pangolin's habitat.

B. The pangolin's diet.

C. The pangolin's behavior.

D. The pangolin's appearance.

单项选择题