问题 选择题

已知:2X+Y2Z,反应中ω(Z的物质的量分数)随温度T的变化如下图所示。下列判断正确的是

A.T1时,v>v

B.正反应的△H<0

C.a、b两点的反应速率va=vb

D.T<T1时,ω增大的原因是平衡向正方向移动

答案

答案:B

T1时,Z的物质的量分数最大,说明反应达到平衡状态,正逆反应速率相等,A不正确;平衡后如果继续升高温度,Z的物质的量分数降低,说明正反应是放热反应,选项B正确;a、b两点的温度不同,反应速率不相同,选项C不正确;T<T1时,ω增大的原因是反应向正方向进行,而并没有达到平衡状态,选项D不正确,答案选B。

单项选择题

An analysis of workplace trends shows that employee perks, a reliable indicator of job market strength, are beginning to make a comeback. While not as Extravagant as those offered in the late 1990s, companies clearly are shifting their focus from workforce reduction to workforce retention. Firms realize that they require a foundation of experienced, trained, and motivated workers. These employers are improving and/ or adding perks to prevent an exodus of workers that could occur as the economy continues improving. They also may be looking further down the road when severe labor shortages are expected to return.

An analysis of perks offered in today’s workplace shows that many of the 1990s-style benefits, such as game rooms and luxury car leases, have been abandoned. The perks that remain popular with employers and employees are those that help workers stay healthy, career focused, and financially stable. Perhaps the most appreciated are those that help individuals maintain work-life balance.

Work-life balance is just one part of the growing concern companies have about the overall emotional and physical health of their workers. Employees who are stressed out or depressed because they do not feel as if they are giving enough attention to the nonwork aspects of their lives ultimately are unproductive. More and more companies also are learning that workers desire the opportunity to grow professionally in the workplace. HewlettPackard, for instance, has boosted its employee education and development budget by 20%.

Nationwide Insurance, based in Columbus, Ohio, established a career-planning website in 2003. The site provides information on company job opportunities, career development, and an in-house mentoring program. Nationwide also is helping to educate its employees in financial matters, acknowledging that workers distracted by such issues on the job are not giving their full attention to the company’s priorities. It is adding classes and seminars on personal finance issues and 401(k) investments.

Sometimes perks simply are about keeping employee morale elevated. Knowing that an improving economy might prompt valued employees to seek new opportunities, the owner of Ticketcity. com has lavished his best performers with tickets to the Masters golf tournament (锦标赛), access to country clubs, and invitations to a management retreat in Sedona, Ariz.

Moreover, even companies that cannot afford to institute costly perks can find ways to make sure current employees are happy. Doug Dorman, vice president of human resources for the Greenville (S.C.) Hospital System explains that there is a definite sense of urgency when it comes to employee retention, knowing that labor shortages are returning. Dorman notes, however, that they have not focused on perks, "but rather on creating a culture of recognition and appreciation. Employees stay when they have good two-way communication with management and are truly appreciated and recognized for their contributions.

Which of the following perks is out-of-date today()

A. a workshop on the recent stock market

B. an expensive car room that can be used at a relatively low rent

C. a vacation to a beautiful scenic spot for relaxation

D. a training on the expertise which may lead to promotion in career

单项选择题