某瓶装保健食品的外包装标签上的部分文字如下图。某同学为了测定该保健食品中CaCO3的质量分数，进行了如下实验：将100片该食品放入一烧杯中，再向其中注入120g（足量）的稀盐酸，直到不再产生气泡时，测得烧杯内剩余物质的总质量为150．2g。（注：该保健食品中其它成分不与盐酸反应）
请你根据以上数据计算：
（1）反应生成气体（CO2）的质量为多少克？
（2）该保健食品中CaCO3的质量分数为多少？
（1）19．8g （2）90%
题目分析：（1）根据质量守恒定律和由题中商标所给信息可知
反应生成气体（CO2）的质量为:0．5g×100+120g-150．2=19．8g;
设100片中含有碳酸钙的质量为X
CaCO3+2HCl=CaCl2+H2O+CO2↑
100 44
X 19．8g
100/x=44/19．8 x=45g
该保健食品中CaCO3的质量分数为:45/50×100%=90%
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| I’m Mike and I come from England. Now I’m 1 at Beijing International School. I’m good 2 all my subjects and I enjoy 3 in China. In 4 , the Olympic Games will be held (举行) in London. It’s 5 news for English people. At that time many foreigners are going to 6 London. My friends and 7 are going to 8 them around Big Ben, Buckingham Palace and 9 because they are very famous in the world. I’m going to 10 with the Chinese 11 in Chinese. But now I don’t know 12 _ Chinese, so I must study it very 13 . From now on, 14 will take me two hours to learn Chinese every day. I’m looking forward 15 the Olympic Games. | |||
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