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1.半径为1cm的铁球表面要镀一层厚度为0.01cm的铜,试用求微 分的方法算出每只球需要用铜多少克?(铜的密度为8.9g/cm3。)

In this chapter, st ability and performance for multivariable systems with uncertainty will be considered. Consider a general multivariable system as depicted in Figure 5.1. All signals will in general be vectors, and G() and K(s) will be transfer matrices. d(s) is an output distur- bance signal and n() represents

一、选择题 1.[]已知地球的质量为m,太阳的质量为M地心与日心的距离为R,引力常数为G,则地球绕太阳作圆周运动的轨道角动量为: (A)mGMR

process can occur spontaneously is that the entropy changes of chemical reactions are not readily measured. Furthermore, the criterion of sponta- neity given in equation 2 requires that both the entropy change of the surroundings and that of the system of interest be known. These difficul- ties are obviated by using different thermodynar function called the free energy, which is denoted by the symbol G (or F, in the older literature)

一、选择题(26分) 1.表达式val(.123e2C”)的值是[ a.0.123b.12.3c.0d..123e2d . variant是一种特殊的数据类型,除了[]和类型外,可以包含任 何种类的数据。 a.固定长度字符串b.字节c.实型d.单精度 e.可变长度字符串f.整形g.货币h.自定义

1.在298K时用Pb(s)电极来电解H2SO4溶液(0.1mol/kg,y±=0.265)若在电 解过程中把Pb阴极与另一摩尔甘汞电极相连组成原电池测得其电动势 E=1.0685V试求H2(g)在Pb电极上的超电势(只考虑H2SO4的一级电离)已知 (甘汞)=0.2802V

1.298K时N2O5(g)分解反应半衰期t为5.h此值与N2O的起始浓度无关试求: (1)该反应的速率常数 (2)作用完成90%时所须的时间

1.如果一个体重为70kg的人能将40g巧克力的燃烧热(628k)完全转变为垂直位移所要作的功,那么这点热量可支持他爬多少高度? 2.在291K和下,1 mol Zn(s)溶于足量稀盐酸中置换出1molH2并放热152kJ。若以Zn和盐酸为体系,求该反应所作的功及体系内能的变化

1.5 mol He(g)从273.15K和标准压力变到98.15K和压力p=10×,求过程的ΔS.(已知Cm=3/2) 2.0.10kg283.2K的水与0.20kg313.2K的水混合,求△S设水的平均比热为4.184k/(kkg)