【单选题】有一原电池: Pt │ Fe 3+ (1 mol/L) , Fe 2+ (1 mol/L) ‖ Ce 4+ (1 mol/L) , Ce 3+ (1 mol/L) │ Pt 则该电池的电池反应是( )
A.
Ce 3+ + Fe 3+ = Ce 4+ + Fe 2+
B.
Ce 4+ + Fe 2+ = Ce 3+ + Fe 3+
C.
Ce 3+ + Fe 2+ = Ce 4+ + Fe 3+
D.
Ce 4+ + Fe 3+ = Ce 3+ + Fe 2+
【判断题】观察洋葱鳞茎内表皮细胞所用的染液通常是醋酸洋红。
【单选题】有一原电池 : - ) Pt│Fe 3+ (1mol·L -1 ) , Fe 2 + (1 mol·L -1 ) ‖ Ce 4 + (1 mol·L -1 ) , Ce 3+ (1 . mol·L -1 ) │Pt ( + ) , 则该电池的电池反应是 ( )
A.
Ce 3 + + Fe 3 + = == Ce 4 + + Fe 2 +
B.
Ce 4 + + Fe 2 + = == Ce 3 + + Fe 3 +
C.
Ce 3 + + Fe 2 + = == Ce 4 + + Fe
D.
Ce 4 + + Fe 3 + == = Ce 3 + + Fe 2 +
【单选题】定义:符号 表示不超过实数x的最大整数,如 , , 等,设函数 ,则下列结论中不正确的是 ( )
【单选题】有一原电池:Pt│Fe3+(1mol.dm-3 ),Fe2+(1 mol.dm-3 )‖Ce4+(1mol.dm-3),Ce3+(1mol.dm-3) ½ Pt则该电池的电池反应是
A.
Ce 3+ + Fe 3+ = Ce 4+ + Fe 2+
B.
Ce 4+ + Fe 2+ = Ce 3+ + Fe 3+
C.
Ce 3+ + Fe 2+ = Ce 4+ + Fe
D.
Ce 4+ + Fe 3+ = Ce 3+ + Fe 2+
【单选题】设 是连续型随机变量X的分布函数,则下列结论中不正确的是( )
【简答题】The devices function together as the coupler which helps to improve the vertical stability of the train .In most cases ,buffer devices are included in couplers to mitigate the train jerk .They are als...
【单选题】What is the main function of the transitional devices in writing?
A.
They serve as the bridges between parts of your paper.
B.
They make your writing simple.
C.
They emphasize your main points.
D.
They help you to express your ideas in an easy way.
【单选题】设F 是连续型随机变量 X的分布函数,则下列结论中不正确的是
【单选题】有一原电池: Pt│Fe 2+ (1 mol·L -1 ) , Fe 3+ (1 mol·L -1 ) ‖ Ce 4+ (1 mol·L -1 ) , Ce 3+ (1 mol·L -1 )│Pt 则该电池的电池反应是
A.
Ce 3+ + Fe 3+ = Ce 4+ + Fe 2+
B.
Ce 4+ + Fe 2+ = Ce 3+ + Fe 3+
C.
Ce 3+ + Fe 2+ = Ce 4+ + Fe
D.
Ce 4+ + Fe 3+ = Ce 3+ + Fe 2+