发酵粉是一种制作风味糕点的常见蓬松剂。某兴趣小组拟对其化学成_爱下问搜题

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问题实验题

发酵粉是一种制作风味糕点的常见蓬松剂。某兴趣小组拟对其化学成分进行如下探究。

【查阅资料】①发酵粉一般含有NH₄HCO₃、NaHCO₃、明矾[KAl(SO₄)₂·12H₂O]中的2种。

②已知反应：2NaHCO₃Na₂CO₃+H₂O+CO₂↑

【提出假设】假设1：有NH₄HCO₃和NaHCO₃；

假设2：有NaHCO₃和明矾；

假设3：有_____①_____和明矾。

【方案与流程】

【问题与讨论】（1）步骤①的操作是在研钵中把发酵粉和熟石灰混合、研磨。

（2）气体A为____②____。若生成A，证明假设____③_____或假设___④______可能成立；若不生成A，证明假设____⑤____成立。

（3）如果生成A，经过步骤②和步骤③后，生成气体B，则B是（填化学式）____⑥____，证明假设___⑦_____成立，写出步骤②的化学方程式________⑧__________。

答案

【提出假设】假设3：NH₄HCO₃

【问题与讨论】（2）氨气（或NH3或刺激性气味的气体）；1；3；2

（3）CO₂；1；NH₄HCO₃NH₃↑+H₂O+CO₂↑

完形填空

I was successful at my job. I worked very hard, but it 36 me and my family a fabulous (极好的) lifestyle. I’d worked for the same company for twenty years and had worked my way up to department director. 37 , one afternoon last May, I was called to the office, and it was 38 explained to me that they were letting me go. I just sat there 39 they talked on and all I could think was, “I’ve 40 .” I’d been so well respected, but 41 I was of no value.
For six weeks, I was in a very 42 place. I wandered around my house like a zombie (僵尸). I could 43 things needed doing, but would not do anything. My beliefs in looking forward and seeing the positive (积极的) in everything 44 me.
Then, in late June, my youngest son’s football team made the city cup final. The year before, he’d been very sad when I 45 the same final, so he was 46 when I told him I’d go. Not only did they win, but the look on his face as he saw me 47 him on was unbelievable, From then on, I spent the summer enjoying my some and their passions (激情). I attended match after match and performances of my elder son’s band — I 48 went to another city to watch him play. These moments were so 49 . My life had been so much devoted to 50 for so long, and I felt 51 that my sons were happy to welcome me into their world.
52 , being unemployed gave me back a sense of purpose --- I was someone’s mum! I felt a sense of being 53 Again. Now I feel more positive about my professional 54 and I’m getting on better with my family than I ever have. Losing my job made me realize just how 55 it is to achieve real balance in life.

C．immediately

A．disappointed

D．performances

C．Disagreeably

D．Unexpectedly

C．relationship

B．interesting

单项选择题

世界卫生组织制订的6个月～6岁小儿Hb正常值的低限为( )

A．90g／L

B．100g／L

C．110g／L

D．120g／L