题干

制作馒头时常加入泡打粉,在制作过程中由于产生二氧化碳气体,使馒头变得松软可口.小明对泡打粉的发面原理产生兴趣,进行了以下实验探究.

【查阅资料】泡打粉是一种复合膨松剂,又称为发泡粉,可作为快速发面剂用于制作面食.某种泡打 粉的主要成分是小苏打粉和酒石酸氢钾.

【提出问题】泡打粉为什么会产生二氧化碳气体?

【猜想】猜想1:小苏打受热分解产生二氧化碳气体

猜想2:酒石酸氢钾受热分解产生二氧化碳气体

猜想3:小苏打和酒石酸氢钾在溶液中发生反应,产生二氧化碳气体

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    When Abraham Lincoln was young, he worked in a store. One day a woman came into the store and bought some things. They added up to two dollars and six and a quarter cents.

    The bill was paid, and the woman was satisfied. But the young storekeeper, not feeling quite sure about his calculations(计算), added up the things again. To his surprise, he found that it should have been but two dollars.

    “I've made her pay six and a quarter cents more,” said young Abe, upset.

    It was an unimportant thing, and many salespersons would forget it, but Abe was too careful for that.

    The money must be paid back, he decided.

    At night, he closed the store and walked to the home of his customer. He explained the matter, paid over the six and a quarter cents, and returned satisfied.

    Here is another story of young Lincoln's strict honesty. A woman entered the store and asked for half a pound of tea. The young man weighed it out. This was the last sale of the day.

    The next morning, when beginning his duties, Abe discovered a four-ounce weight on the scales(磅砰). It flashed upon him at once that he had used this in the sale last night, and so, of course, given his customer short weight. Many people would not have been much worried by this discovery. But Abe weighed out four ounces of the tea, shut up the store, and carried it to the customer. I think that the name, so often given in late times to President Lincoln, of “Honest Old Abe", was well deserved(应得的).