题干

 实验测得0.5kg某物质温度随时间变化的图象如图示,已知物质在固态下的比热容为C1=2.1×103J/(kg℃).假设这种物质从热源吸热的功率恒定不变,根据图象解答下列问题:

(1)在最初的 2min内,物质吸收的热量为多少?(1分)
(2)求该物质在液态下的比热容C2
(3)若规定“质量为1Kg的某种晶体物质在完全熔化时所吸收的热量叫做这种物质的熔化热” 用“λ”表示,根据图像信息,计算该物质的熔化热。

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答案(点此获取答案解析)

解:(1)在最初的2min内,由图像可知物质的温度变化是20℃,物质吸收的热量为Q=cm△t=2.1×103J/(kg℃)×0.5kg×20℃=2.1×104J(2)假设这种物质从热源吸热的功率恒定不变,在2min内吸收的热量是2.1×104J,从图像可知物质液态时在第10min到第12min温度的变化是10℃,所以此时的比热容是C2=2.1×104J /(0.5kg×10

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阅读下面的短文,掌握其大意,然后从短文后各题所给的A、B、C、D四个选项中,选择最佳选项。
                                                                Real Solutions(解决方法) to Problems

    Thirty engineers were working as a team in a company. They were young and eager to learn. The management decided to teach them about finding real solutions to problems

    One day, the team was called for a 1in a hall. They were quite surprised and all reached the hall holding various2. As they entered, they found a box placed in the center, full of flat balloons

    The manager asked everyone to pick a balloon and blow it up. Then they were asked to write their names on their respective(各自的)balloons 3so that the balloons wouldn't blow out. All tried, but not everyone was 4. Five balloons blew out due to pressure(压力).

    Those who failed to mark their names on the balloons were 5 out of the game. As a result, 25 engineers came to the next level. All the balloons carrying their names were 6 and then put into a room, here and there.

    The engineers were told to pick the balloon with his or her name on. All the 25 engineers began to search for the respective balloons in a rush. It was almost 15 minutes but no one was able to 7 the right one. The second level of the game was over.

    Then came the final level, the engineers were asked to pick any balloon and give it to person named on the balloon. Within a couple of minutes, all balloons 8 the hands of the respective engineers.

    The manager announced this was the real solution to the problem. Many times in our life, sharing and helping others give us real solutions to problems.