问题 选择题

下列说法正确的是

A.氨气是非电解质,氨水是电解质

B.氢氧化铁胶体可以发生丁达尔现象

C.摩尔和物质的量均是联系宏观和微观数量的物理量

D.二氧化硅既可和酸又可和碱反应,所以二氧化硅是两性氧化物

答案

答案:B

题目分析:A、溶于水或在熔融状态下能够自身电离出离子的化合物是电解质,溶于水和在熔融状态下均不能自身电离出离子的化合物是非电解质。氨气不能自身电离,是非电解质。氨水是混合物,不是电解质,也不是非电解质,A不正确;B、胶体可以发生丁达尔效应,据此可以检验溶液与胶体,B正确;C、摩尔是物质的量的单位,不是物理量,C不正确;D、二氧化硅只能与氢氟酸反应生成四氟化硅和水,与碱反应生成盐和水,因此二氧化硅是酸性氧化物,不是两性氧化物,D不正确,答案选B。

填空题
阅读理解

If you think American cooking means opening a package and throwing the contents into the microwave oven (微波炉), think again. On the one hand, it’s true that many Americans have cold cereal for breakfast, sandwiches for lunch and instant (方便的) dinners. From busy homemakers to working people, many Americans enjoy the convenience (方便) of fast food that can be ready to serve in 10 minutes or less. On the other hand, many Americans realize the importance of cooking skills. Parents — especially mothers — see the importance of training their children — especially daughters. Most Americans think that there’s nothing better than a good home-cooked meal. But with cooking, as with any other skill, good results don’t happen by accident.

Probably every cook has his or her own way of cooking. But there are some basic skills that most people follow. For example, baking is a main method (方法) of preparing food in America. For that reason, Americans would find it next to impossible to live without an oven. American cooks pay special attention to the balance of foods, too. In planning a big meal they try to include meat, a few vegetables, some bread and often a dessert. They also like to make sure the meal is colorful. Having several different colors of food on the plate usually makes for a healthy meal.

For those who need guidance in their cooking, or for those who have just run out of ideas, recipes are a great help. Recipes list all the ingredients for a dish (generally in the order used), the amount of each to use, and a description of how to put them together.

小题1:This passage mainly tells us that ______.

A.Americans like to have several different colors of food on the plate

B.without an oven, Americans find it impossible to live conveniently

C.Americans pay special attention to recipes and nutritious meals

D.Americans usually have fast food, but they pay special attention to cooking as well小题2:Many Americans have cold cereal for breakfast, sandwiches for lunch and instant dinner because ______.

A.they like instant food very much

B.they don’t like cooking at all

C.most American working people are busy and don’t have time to cook

D.fast food is delicious and it usually contains a lot of vitamins小题3:By saying “But with cooking, as with any other skill, good results don’t happen by accident”, the author means ______.

A.good cooking doesn’t come easily; it needs a lot of practice

B.just like any other skill, cooking may bring good results

C.cooking comes from one’s gift, not through practice

D.cooking can lead to accidents小题4:From the passage, we know that ______.

A.Americans don’t care about food

B.Americans are not good at cooking because they like to use recipes

C.an oven plays an important role in cooking for Americans

D.while cooking, Americans usually run out of ideas