问题 问答题

有三种固体粉末,分别是二氧化锰、活性炭和氯酸钾.现仅提供初中化学实验常用仪器,请设计一个实验方案区分这三种固体;并在下表中用文字叙述实验操作、预期现象和结论.

实验操作预期现象与结论

答案

根据三种物质的不同性质,首先从颜色、状态上鉴别出氯酸钾,然后根据是否有可燃性鉴别出活性炭,故答案为:

实验操作预期现象与结论
分别取样,观察.白色粉末为氯酸钾,黑色粉末为二氧化锰或活性炭.
分别取少量黑色粉末,在空气中灼烧.能燃烧,有发光或火星飞溅现象的是活性炭,没有明显变化现象的是二氧化锰.

单项选择题
阅读理解

The eastern Indonesian Island of Komodo is proving a hit with adventurous tourists eager to catch a glance of the world’s largest lizard species. The island is the home of the huge lizard called the Komodo dragon.

A later species of the Jurassic period dinosaurs 130 million years ago, the Komodo dragon is in danger and has been placed under protection by the Indonesian government.

The huge lizard is called “Buaya Darat” by the local people who show great respect for the species. Tales handed down over generations of islanders speak of the dragon warning people of getting close to crocodiles.

The animal can reach a length of three meters when fully grown, gain a weight of about 135 kilograms and may live to an age of about 100 years. It digs a hole in the ground as deep as 9 meters and lay eggs---up to 30 at a time---that hatch in April or May. The newly hatched lizards, about 45 centimeters long, live in trees for several months.

Komodo dragons have been known to eat smaller members of the species and sometimes even other grown-ups. The Komodo dragon was first discovered in 1912 by a group of fishermen who protected themselves from a storm in the Banda Sea on the island.

Various species of the Komodo dragons are also found in Asia, Australia and Africa, but it is only on Komodo and the western tip of the neighboring island of Flores that they grow up to three meters long.

46. The message is mainly about                                  .

the largest crocodile in the world                      B. the story of a dragon in Indonesia

a kind of huge lizard---the Komodo dragon 

D. how the Komodo dragon was found and protected

47. Newly-born Komodo dragons                                 .

A. dig very deep holes            

B. are hatched in cold weather

C. are 30 centimeters long and weigh 45 kilograms 

D. spend their first few months living in trees

48. Today Komodo dragons                                      .

A. are protected by the local government   

B. are hunted by Komodo fishermen

C. join in a special hatching program      

D. live only on the Komodo Island

49. According to the passage, Komodo dragons                              .

are 9 meters long and live up to 80 years

are 3 meters long and live up to 100 years

weigh up to 135 kilograms and are 9 meters long

weigh 45 kilograms and live up to 135 years

50. The local people have great respect for the Komodo dragon because they believe ___        

the dragon can prevent them from being attacked by crocodiles

the dragon has special curing power

the dragon is in great danger of dying out in its hometown

it takes thousands of years for the dinosaurs to become dragons