I worked for a short time as a cashier at a restaurant a few months ago. I also helped to clean up the tables when it was very busy. One night, just before Christmas, I found a large black wallet on the floor near one of the tables. I guessed I should check it to find out who was the owner, but I was very busy at the time. And I imagined that if there was something valuable in the wallet, the owner would be back. Sure enough, an hour later a man came up to the counter and asked if anyone had found a wallet. l asked him to describe the lost wallet, and after he described it exactly, I gave him the wallet. He expressed his thanks when I handed it to him. He asked me if I had opened it, and when I told him “no”. At once he opened it and showed that it had nearly $800 in cash. He took out a twenty-dollar bill and handed it to me and I was amazed at this. “A reward for your honesty,” he said and then turned and walked away.
Thinking about it later, I began wondering whether I would have been honest if had known what was in the wallet! I thought that if I had no way to find the owner and no one returned to get it, I might keep it. But it also came into my mind that I actually saved someone's Christmas plans by finding and returning the wallet. The good feeling it gave me was worth more than anything could buy.
Which of the following is true?( )
由于作者并未打开钱包,更没有从中取出什么,所以说“Nothing in the wallet was missing”。
把10gMgCl2和MgSO4的混合物溶于适量水中,滴加2mol/L的BaCl2溶液至沉淀完全,共消耗BaCl2溶液25mL。求混合物中MgCl2和MgSO4的质量各是多少克
固定在匀强磁场中的正方形导线框abcd,各边长为1.其中ab是一段电阻为R的均匀电阻丝,其余3边均为电阻可忽略的铜线。磁场的磁感应强度为B,方向垂直纸面向里。现有一与ab段的材料、粗细、长度都相同的电阻丝PQ架在导体框上,如图所示。PQ以恒定速度方向如何
一小物块以速度v0=10m/s沿光滑地面滑行,然后沿光滑曲面上升到顶部水平的高台上,并由高台上飞出,如图所示。问当高台的高度h多大时,小物块飞行的水平距离最大这个距离是多少(g=10m/s2)
某晶体盐的水溶液呈浅绿色,在此溶液中通入氯气,溶液变为棕黄色,把所得棕黄色溶液分成两份:一份加入KSCN溶液,溶液变深红色;另一份加入BaCl2溶液,产生不溶于稀HNO3的白色沉淀,则该晶体盐的化学式是_______。
欲除去乙烷中的乙烯,可将混合气体通过盛有_______的洗气瓶;欲除去乙炔中的硫化氢,可将混合气体通过盛有_______的洗气瓶。
浓硝酸常盛装在棕色瓶中,且贮放在冷暗处,原因是_______,
碳酸氢钠溶液和烧碱溶液反应的离子方程式为_______。
常温下,氨水中存在的离子有_______。
在酸或碱存在的条件下,甲酸甲酯跟水发生水解反应的化学方程式为_______。
有下列几种气体:H2、O2、HCl、NO、NH3、CH4,其中通常情况下能用来和水做“喷泉”实验的是_______。