计算0.10mol/LNH4Cl溶液的pH(Kb=1.8×10-5)
参考答案:
=7.5×10<sup>-6</sup>(mol/L)
pH=5.12
从6名短跑运动员中选出4人参加4×100 m接力赛.试求满足下列条件的参赛方案各有多少种?
(1)甲不能跑第一棒和第四棒;
(2)甲不能跑第一棒,乙不能跑第四棒
—Excuse me, could you tell me _____ later on?
—Wait a minute. It is coming in ten minutes.[ ]
A. if the next train arrives
B. if the next train will arrive
C. when the next train arrives
D. when will the next train arrive