Ⅰ 固体的成分分析
【提出问题】该瓶氢氧化钠固体是否变质,变质情况如何?
【查阅资料】
①氢氧化钠在空气中容易变质但不会转化为NaHCO3;
②CaCl2溶液的pH=7,碳酸钠溶液的pH›7
③CaCl2+Na2CO3═CaCO3↓+2NaCl
Ca(OH)2+Na2CO3═CaCO3↓+2NaOH
④碱石灰是CaO和NaOH的混合物
【提出猜想】
猜想Ⅰ:固体未变质
猜想Ⅱ:固体全部变质
猜想Ⅲ:固体部分变质
下列各句中,没有语病的一项是( )
Tai Lihua is a Chinese woman. She is very beautiful. As a child, she became deaf and dumb(哑的). She couldn't hear or say. She was very sad. Later, she had a teacher. The teacher taught her to dance. Though she couldn't hear, she was very hardworking. She danced very well. Now, she is very famous. She is not sad any more.