下列鉴别各组物质的方法不正确的是（ ）
A．用肥皂水鉴别硬水和软水
B．用盐酸鉴别氯化钠和碳酸钠
C．用燃着的木条鉴别氨气和二氧化碳
D．用水鉴别硝酸铵固体和氢氧化钠固体
答案：C
题目分析：A、区分硬水和软水的方法是：用肥皂水，加入肥皂水，泡沫多的是软水，泡沫少的是硬水，正确；
B、用盐酸鉴别氯化钠和碳酸钠，有气泡冒出的是碳酸钠，无变化的是氯化钠，正确；
C、用燃着的木条鉴别氨气和二氧化碳，木条都熄灭，无法鉴别，错误；
D、用水鉴别硝酸铵固体和氢氧化钠固体，溶于水温度升高的是氢氧化钠固体，溶于水温度降低的是硝酸铵固体，正确；
故选C
点评：本考点属于物质的鉴别题，是通过对实验方法和过程的探究，在比较鉴别的基础上，得出了正确的实验结论．本考点是中考的重要内容之一，主要出现在填空题和实验题中．
根据短文内容，选出5个句子填入文中空缺处，使短文内容完整正确，其中一项为多余选项。 Which university would you like to go to in the future? It’s not too early to think about it right now. Students at Hilltop School had a University Week at the end of last month.小题1: For instance, they designed a flag for a virtual(虚拟的) “University of Hilltop”. 小题2: He said he started the program to help students form their aims. “University may not be for everyone, but we want the program to help students form their aims.” He said. 小题3: Eric ,a student in Grade 8,said“University Week made me realize that university is only four years away. I should do research about where I want to go.” Paul, another student in Grade 8 said that he realized there were so many universities for him to choose. 小题4: The school also invited people to give career talks. The first talk was given by Captain Brown, a policeman. He talked about how to choose a career way. 小题5: “The program opened up the students’ eyes.” said Mr Miller.
|