问题 填空题

硫化钠是重要的工业原料。

(1)高温时,等物质的量甲烷与硫酸钠在催化剂作用下恰好完全反应,制得硫化钠。反应的化学方程式为__________________。

(2)甲同学往某Na2S样品(含Na2CO3、Na2SO4杂质)溶液中加人少量BaS溶液,产生白色沉淀,过滤,向滤渣中加人过量盐酸,沉淀完全溶解。由此得出结论:相同温度下,Ksp(BaCO3)<Ksp(BaSO4)。

①沉淀溶于盐酸的离子方程式是__________________。

②仅由上述实验无法判断Ksp(BaCO3)与Ksp(BaSO4)的大小关系,理由是______。

(3)利用Na2S为沉淀剂由锌灰可制得ZnS。锌灰经稀硫酸浸取后所得浸取液含Zn2+、Cd2+、Al3+、Fe2+, Fe3+等,由该浸取液制备ZnS的工艺流程如下图所示。

①步骤(i)所得滤渣中含有铝元素的物质为______(填化学式)。

②步骤(ii)所加ZnO的作用为____________。

③步骤(iii)中得到Cd单质的离子方程式为____________。

答案

(15分)

(1)CH4+Na2SO4Na2S+CO2+2H2O(3分)

(2)BaCO3+2H+=Ba2++CO2↑+H2O(3分)

沉淀的形成除了与Ksp有关外,还与溶液中沉淀组分的离子浓度大小有关(或其他合理答案)(2分)

(3)①Al(OH)3(2分)

②调节溶液的pH,使Fe3+形成Fe(OH)3沉淀(2分)

③Cd2++Zn=Cd+Zn2+(3分)

题目分析:(1)、硫酸钠变为硫化钠时,硫元素由+6价降为—2价,由此推断甲烷中碳元素的化合价升高,由—4价升为+4价,生成CO2,根据最小公倍数法配平可得反应式CH4+Na2SO4Na2S+CO2+2H2O;(2)、Na2CO3、Na2SO4与BaS溶液均能反应生成白色的沉淀,但是BaCO3能溶于盐酸,反应式为BaCO3+2H+=Ba2++CO2↑+H2O,而BaSO4不溶于盐酸,但是不能说明Ksp(BaCO3)<Ksp(BaSO4),因为沉淀的形成除了与Ksp有关外,还与溶液中沉淀组分的离子浓度大小有关(或其他合理答案);(3)、①pH=5时,Al3+几乎完全沉淀,则步骤(i)所得滤渣含有铝元素的物质为Al(OH)3;②步骤(ii)所加H2O2/H+的目的可以使Fe2+完全氧化为Fe3+,所加ZnO固体可以消耗溶液中的H+,减小H+浓度,使Fe3+彻底水解为Fe(OH)3沉淀,从而除铁;③步骤(iii)所加Zn能还原Cd2+,反应式为Cd2++Zn=Cd+Zn2+,从而除镉。

阅读理解

     Five Olympic mascots were announced exactly 1000 days before the Beijing Olympic opening

ceremony. The long-anticipated mascots represent four of China's most popular animals—the fish, the

panda, the Tibetan antelope and the swallow. The fifth mascot is the brightly burning Olympic flame.

     Each of the mascots has a repeated two-syllable name. This type of name is a traditional way of

showing affection for children in China. BeiBei is the fish, JingJing is the panda, HuanHuan is the Olympic

flame, YingYing is the Tibetan antelope and NiNi is the swallow. The first characters of their two-syllable

names read "Beijing Huanying Ni," or, in English, "Welcome to Beijing."

     The five elements of nature, including the sea, forest, fire, earth and sky are found in the mascot's

origins and headpieces. These special headpieces also display the folk and culture of China. Each mascot

also symbolizes a different blessing —prosperity, happiness, passion, health and good luck.

     It is the first time more than three mascots will share the important duty of representing their host

country. Han Meilin, chief of the mascot design team explained that, "China has such a rich culture that no

single mascot could possibly represent it! That is why we chose to produce five mascots instead of one."

     Called the "Five Friendlies," the figures embody(体现) the Chinese people's hope for peace and

friendship in the world and the spirit of the Olympics, representing not only multi-ethnic(多民族的)

cultures of China, but also the traditional Chinese philosophy of harmony between humans and nature.

     In order to help Beijing 2008 spread its theme of One World, One Dream to every continent, the Five Friendlies reflect the deep desire of the Chinese people to reach out to the world in friendship through the Games - and to invite every man, woman and child to take part in the great celebration of human union in

2008.

1. What's the theme of Beijing 2008 Olympics?

A. Welcome to Beijing.

B. Prosperity, Happiness, Passion, Health and Good luck.

C. New Beijing, New Olympics.

D. One World, One Dream.

2. What did Han Meilin, chief of the mascot design team, think of the five mascots?

A. He thought highly of the five mascots.

B. No single mascot could represent China.

C. The five mascots represented the culture of China.

D. They would reflect the desire of Chinese people.

3. Which of the following statements is not true?

A. It's for the first time that five mascots are chosen to represent their host country in the Olympic history.

B. One of the five mascots YingYing stands for the Olympic flame.

C. Beijing announced its five 2008 Olympic mascots just 1000 days before the big event.

D. The five mascots express affection for Chinese children by two-syllable names.

4. Which of the following best reflects the main idea of the passage?

A. The 29th Olympic Games will be held in Beijing in 2008.

B. The theme of 2008 Beijing Olympics - One World, One Dream.

C. The significance of five 2008 Olympic mascots - the Five Friendlies.

D. How the Five Fantastic Mascots came into being.

5. What do the five mascots - the Five Friendlies represent?

A. "Beijing Huanying Ni," or, in English, "Welcome to Beijing."

B. Chinese multi-ethnic cultures, philosophy of harmony between humans and nature and five elements

of nature.

C. Chinese people's hope for peace and friendship in the world and the spirit of the Olympics.

D. The deep desire of the Chinese people to reach out to the world in friendship through the Olympics.

判断题