问题 填空题

(1)0.1mol/LNa2CO3溶液呈______(填“酸性”、“碱性”或“中性”),其原因是______(用离子方程式表示)

(2)氢氧燃料电池是利用氢能的一种重要方式.请写出氢氧燃料(电解质溶液为KOH溶液)的负极的电极反应式______.

(3)某温度下的水溶液中,c(H+)=10-xmol/L,c(OH-)=10-ymol/L.x与y的关系如图1所示:该温度下水的离子积为______;该温度下0.01mol/L NaOH溶液的pH为______.

(4)如图2装置,已知两电极上发生的电极反应分别为:a极:Cu2++2e-=Cu    b极:Fe-2e-=Fe2+

该装置中原电解质溶液一定含有______ (填序号)

A. Cu2+ B.Na+    C.Fe2+   D. Ag+

(5)硫酸钡在水中存在沉淀溶解平衡:BaSO4(s)⇌Ba 2+ (aq)+SO42-(aq) 25℃时,BaSO4的Ksp=1.1×l0-10,在0.1mol•L一1硫酸溶液中,钡离子的浓度最大可达到______mol•L一1

答案

(1)Na2CO3为强碱弱酸盐,溶液中CO32-水解呈碱性,水解离子方程式为CO32-+H2O⇌HCO3-+OH-

故答案为:碱性; CO32-+H2O⇌HCO3-+OH-

(2)负极氢气失电子被氧化,电极反应式为2H2+4OH--4e-=4H2O,故答案为:2H2+4OH--4e-=4H2O;

(3)根据图象对应的横坐标和从坐标的数值可知Kw=c(OH-)×c(H+)=10-8×10-4=1×10-12,该温度下0.01mol/L NaOH溶液中c(H+)=

10-12
0.01
=10-10moL/L,溶液的pH为10,

故答案为:1×10-12; 10;

(4)根据电极方程式可知溶液中应含有Cu2+,故答案为:A;

(5)Ksp=1.1×l0-10=c(SO42-)×c(Ba2+),c(Ba2+)=

1.1×10-10
0.1
mol/L=1.1×10-9mol/L,故答案为:1.1×10-9

选择题
阅读理解

阅读理解.

     If your boss asks you to work in Moscow this year, he'd better offer you more money to

do so-or even double that depending on where you live now.That's because Moscow has

just been found to be the world's most expensive city for the second year in a row by Mercer

Human Resources Consulting.

     Using the cost of living in New York as a base, Mercer determined Moscow is 34.4

percent more expensive including the cost of housing,transportation, food, clothing,

household goods and entertainment(娱乐).

     A twobedroom flat in Moscow now costs $4,000 a month; a CD $24.83, and an

international newspaper $6.30, according to Mercer.By comparison, a fast food meal

with a hamburger(汉堡包) is a_steal at $4.80.

     London takes the No.2 place, up from No.5 a year ago, thanks to higher cost of

housing and a stronger British pound relative to the dollar.Mercer estimates(估算)

London is 26 percent more expensive than New York these days.Following London

closely are Seoul and Tokyo, both of which are 22 percent more expensive than New

York, while No.5 Hong Kong is 19 percent more costly.

     Among North American cities, New York and Los Angeles are the most expensive

and are the only two listed in the top 50 of the world's most expensive cities.But both

have fallen since last year's study-New York came in 15th, down from 10th place, while

Los Angeles fell to 42nd from 29th place a year ago.San Francisco came in a distant

third at No.54, down 20 places from a year earlier.

     Toronto, meanwhile, is Canada's most expensive city but fell 35 places to take 82nd

place worldwide.In Australia, Sydney is the priciest place to live in and No.21 worldwide.

1. What do the underlined words "a steal" in Paragraph 3 mean?

A.an act of stealing.

B.something delicious.

C.something very cheap.

D.an act of buying.

2.London has become the second most expensive city because of ________.

A.the high cost of clothing

B.the stronger pound against the dollar

C.its expensive transportation

D.the high prices of fast food meals

3. Which city is the third most expensive on the list?

A.Tokyo.

B.Hong Kong.

C.Moscow.

D.Sydney.

4.Which city has dropped most on the list in North America?

A.New York.

B.Los Angeles.

C.San Francisco.

D.Toronto.