问题 单项选择题

When Liam McGee departed as president of Bank of America in August, his explanation was surprisingly straight up. Rather than cloaking his exit in the usual vague excuses, he came right out and said he was leaving “to pursue my goal of running a company.” Broadcasting his ambition was “very much my decision,” McGee says. Within two weeks, he was talking for the first time with the board of Hartford Financial Services Group, which named him CEO and chairman on September 29.
McGee says leaving without a position lined up gave him time to reflect on what kind of company he wanted to run. It also sent a clear message to the outside world about his aspirations. And McGee isn’t alone. In recent weeks the No.2 executives at Avon and American Express quit with the explanation that they were looking for a CEO post. As boards scrutinize succession plans in response to shareholder pressure, executives who don’t get the nod also may wish to move on. A turbulent business environment also has senior managers cautious of letting vague pronouncements cloud their reputations.
As the first signs of recovery begin to take hold, deputy chiefs may be more willing to make the jump without a net. In the third quarter, CEO turnover was down 23% from a year ago as nervous boards stuck with the leaders they had, according to Liberum Research. As the economy picks up, opportunities will abound for aspiring leaders.
The decision to quit a senior position to look for a better one is unconventional. For years executives and headhunters have adhered to the rule that the most attractive CEO candidates are the ones who must be poached. Says Korn/Ferry senior partner Dennis Carey:” I can’t think of a single search I’ve done where a board has not instructed me to look at sitting CEOs first.”
Those who jumped without a job haven’t always landed in top positions quickly. Ellen Marram quit as chief of Tropicana a decade age, saying she wanted to be a CEO. It was a year before she became head of a tiny Internet-based commodities exchange. Robert Willumstad left Citigroup in 2005 with ambitions to be a CEO. He finally took that post at a major financial institution three years later.
Many recruiters say the old disgrace is fading for top performers. The financial crisis has made it more acceptable to be between jobs or to leave a bad one. “The traditional rule was it’s safer to stay where you are, but that’s been fundamentally inverted,” says one headhunter. “The people who’ve been hurt the worst are those who’ve stayed too long.”

It can be inferred from the last paragraph that

A.top performers used to cling to their posts.
B.loyalty of top performers is getting out-dated.
C.top performers care more about reputations.
D.it’s safer to stick to the traditional rules.

答案

参考答案:D

填空题

Ⅰ.描述弱电解质电离情况可以用电离度(电离度:一定条件下,当弱电解质达到电离平衡时,溶液中已电离的电解质分子数占原电解质分子总数的百分数)和电离平衡常数表示,下表1是常温下几种弱酸的电离平衡常数(Ka)和弱碱的电离平衡常数(Kb),表2是常温下几种难(微)溶物的溶度积常数(Ksp)。

请回答下面问题:

⑴下列能使醋酸溶液中CH3COOH的电离度增大,而电离常数不变的操作是_______(填序号)。

A.升高温度     B.加水稀释     C.加少量的CH3COONa固体       D.加少量冰醋酸

⑵CH3COONH4的水溶液呈______(选填“酸性”、“中性”、“碱性”),理由是____________________。

⑶工业中常将BaSO4转化为BaCO3后,再将其制成各种可溶性的钡盐(如:BaCl2)。具体做法是用饱和的纯碱溶液浸泡BaSO4粉末,并不断补充纯碱,最后BaSO4转化为BaCO3。现有足量的BaSO4悬浊液,在该悬浊液中加纯碱粉末并不断搅拌,为使c(SO42- )达到0.0l mol/L以上,则溶液中c(CO32- )应≥_______ mol/L。

Ⅱ.化学在能源开发与利用中起着重要的作用,如甲醇、乙醇、二甲醚(CH3OCH3)等都是新型燃料。

⑴乙醇是重要的化工产品和液体燃料,可以利用下列反应制取乙醇。

2CO2(g)+6H2(g)CH3CH2OH(g)+3H2O(g)  △H=a kJ/mol 在一定压强下,测得上述反应的实验数据如下表。

根据表中数据分析:

①上述反应的 a_______0(填“大于”或“小于”)。

②在一定温度下,提高氢碳(即n(H2)/n(CO2) )比,平衡常数K值_______(填“增大”、“减小”、或“不变”),对生成乙醇______(填“有利”或“不利”)。

⑵催化剂存在的条件下,在固定容积的密闭容器中投入一定量的CO和H2,同样可制得乙醇(可逆反应)。该反应过程中能量变化如图所示:

①写出CO和H2制备乙醇的热化学反应方程式_________________。

②在一定温度下,向上述密闭容器中加入1 mol CO、3 mol H2及固体催化剂,使之反应。平衡时,反应产生的热量为Q kJ,若温度不变的条件下,向上述密闭容器中加入4 mol CO、

12 mol H2及固体催化剂,平衡时,反应产生的热量为w kJ,则w的范围为___________。

⑶二甲醚(CH3OCH3)被称为21世纪的新型燃料,具有清洁、高效的优良性能。以二甲醚、空气、氢氧化钾溶液为原料,石墨为电极可构成燃料电池,其工作原理与甲烷燃料电池原理相类似。该电池中负极上的电极反应式是_________________。

选择题