问题 选择题

在电解水时,在水中加入少量硫酸或氢氧化钠是为了(  )

A.防止发生事故

B.增强水的导电性

C.得到更多的氧气

D.得到更多的氢气

答案

A、本实验一般不会发生实验事故,且加入硫酸或氢氧化钠也不会防止事故的发生,所以A不正确;

B、硫酸和氢氧化钠的溶液具有良好的导电性,而纯水导电性很弱,反应较慢,所以在水中加入少量硫酸或氢氧化钠是为了增强水的导电性,所以B正确;

C、电解水时,加入硫酸或氢氧化钠后参加反应的物质依然只有水,不会增加生成物质的质量,即不会得到更多的氧气,所以C不正确;

D、电解水时,加入硫酸或氢氧化钠后参加反应的物质依然只有水,不会增加生成物质的质量,即不会得到更多的氢气,所以D不正确;

故选B.

阅读理解

阅读理解。

                                                    Food. Drink & Refreshment

     Relax and unwind in our new state of the Loch Ness Eatery. Whether you are looking for a snack

or a full meal we can provide almost anything to suit everyone. We will be ready for helping you at all times.

     Fresh Tea. Coffee, Hot Chocolate etc.

     Good choice of Home Baking and Cake.

     Home Made Soup and Sandwiches.

     Sweets and Soft Drinks l Packed to aches for those who prefer a picnic.

     Seating for over 150 visitors. 

                                                                                                                          Tel: +44(0)456 450321

                                                                                                                          Web: www. lochness.com

1. The above reading is most probably _____. [ ]

A. an advertisement

B. a food report

C. a shopping list

D. a menu

2. It's clear that the Eatery _____. [ ]

A. can hold 150 people at most

B. only provides Chinese food

C. was set up in the year of 1980

D. doesn't offer many choices

3. At the loch Ness Eatery, visitors can _____. [ ]

A. book comfortable room

B. have a picnic

C. cook for themselves

D. get a good relaxation

4. The reading also tells us ______. [ ]

A. the prices of food and drinks

B. the address of the Eatery

C. the name of the manager

D. the way of getting in touch with the Eatery

5. The Eatery provides almost everything to _____.  [ ]

A. to serve people for a long time

B. meet the needs of different visitors

C. let people take away

D. help people learn about people

填空题