问题 填空题

(1)Fe(OH)3胶体制备,是向沸腾的蒸馏水中加入几滴饱和FeCl3溶液并继续加热至液体变成红褐色,写出制备Fe(OH)3胶体的化学方程式______,Fe(OH)3胶体中常混有FeCl3和HCl,将其装入半透膜袋,浸入蒸馏水中进行分离,该分离方法称为______,若在盛有红褐色Fe(OH)3胶体的U形管的两个管口插上电极,并通直流电,一段时间后,______极(填阴、阳)颜色变深.

(2)分类方法是研究物质和化学反应的重要方法.

对HCl(盐酸)、H2SO4(硫酸)、HNO3(硝酸)、H3PO4(磷酸)、H2S(氢硫酸)进一步分类时有多种分类角度,根据某些标准进行分类.

①根据某分类标准,只有一种物质与HCl同属一类,该物质是______,分类标准是______

②氧化钙、氢氧化钙分别与盐酸反应的共同点是______,由此可得出氧化钙属于碱性氧化物.根据上述信息的启示,N2O5与氢氧化钠溶液反应的离子方程式是______.

答案

(1)制备胶体的原理是利用铁离子水解生成氢氧化铁胶体,反应的化学方程式为:FeCl3+3H2O═Fe(OH)3(胶体)+3HCl;Fe(OH)3胶体中常混有FeCl3和HCl,分离应采用渗析的方法;Fe(OH)3胶粒吸附了正电荷,通直流电一段时间,向阴极移动,阴极附近的颜色逐渐变深,故答案为:FeCl3+3H2O═Fe(OH)3(胶体)+3HCl;渗析;阴;

(2)①H2S和HCl都是无氧酸,H2SO4(硫酸)、HNO3(硝酸)、H3PO4(磷酸)都是含氧酸;故答案为:H2S;是否是无氧酸;

②氧化钙、氢氧化钙分别与盐酸反应都生成盐和水;N2O5与氢氧化钠溶液反应:N2O5 +2NaOH═2NaNO3+H2O,离子方程式:N2O5 +2OH-═2NO3-+H2O,故答案为:都生成盐和水;N2O5 +2OH-═2NO3-+H2O;

问答题 简答题
阅读理解

B

People have strange ideas about food. For example, the tomato is a kind of very delicious vegetable. It is one of useful plants that can be prepared in many ways. It has rich nutrition and vitamin in it. But in the 18th century, Americans never ate tomatoes. They grew them in their gardens because tomato plants are so pretty. But they thought the vegetable was poisonous (有毒的). They called tomatoes “poison apples.”

President Thomas Jefferson, however, knew that tomatoes were good to eat. He was a learned man. He had been to Paris, where he learned to love the taste of tomatoes. He grew many kinds of tomatoes in his garden. The President taught his cook a way for a cream of tomato soup. This beautiful pink soup was served at the President’s party. The guests thought the soup tasted really good. They never thought their president would serve his honored guests poison apples. Jefferson never spoke to his honored (忠实的) guests about the fact.

46. After you read the passage, which of the following do you think is true?

A. Americans never ate tomatoes after they began to plant them.

B. Americans didn’t eat tomatoes before 19th century.

C. Even now Americans don’t eat tomatoes.

D. In the 18th century Americans ate a lot of tomatoes.

47. The passage tells us that Jefferson was a President who learned to love the taste of tomatoes       .

A. while he was in Paris           B. when he was a little boy

C. because his parents told him so   D. from books

48. According to the text, _______ made the beautiful pink soup served at the President’s party?

A. the President himself        B. a French cook

C. the President’s cook         D. the President’s wife

49. From the passage we know all the honored guests invited by Jefferson were      .

A. people from other countries           B. from France

C. people of his own country             D. men only

50. According to the passage, which of the following is NOT true?

A. All of the guests knew the soup that was served at the President’s party was made of tomatoes.

B. All of the guests thought the soup which was prepared by the President’s cook was nice.

C. All of the guests thought the taste of the beautiful pink soup was nice.

D. None of the guests knew that their president would serve his honored guests poison apples.