问题
选择题
使铁片和银片保持接触并放入相同物质的量浓度的下列物质的溶液中，反应一段时间后，溶液质量减小的是( )
A．氯化铝
B．硫酸铜
C．硝酸钠
D．稀硫酸
答案
答案：B
形成FeAg原电池，Fe被腐蚀，将Cu置换出来，溶液质量减轻，B项可选；将H2置换出来，溶液质量增重，A、C两项发生吸氧腐蚀，溶液质量增重。
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使铁片和银片保持接触并放入相同物质的量浓度的下列物质的溶液中，反应一段时间后，溶液质量减小的是( )
A．氯化铝
B．硫酸铜
C．硝酸钠
D．稀硫酸
答案：B
形成FeAg原电池，Fe被腐蚀，将Cu置换出来，溶液质量减轻，B项可选；将H2置换出来，溶液质量增重，A、C两项发生吸氧腐蚀，溶液质量增重。
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| Having breakfast is a good way to keep healthy. 1 is not only the most important meal of the day, it is also the most neglected (被忽视). If breakfast doesn't appear (吸引) to you in the 2 , try eating a lighter dinner earlier in the 3 or save half your dinner for the breakfast in the morning. If you are not hungry in the morning, start 4 some thing small like juice or toast or have a nutritious (有营养的) mid-morning snack when you are hungry. Some people fear (担心) eating breakfast will make them 5 during the day and they will eat more. It is true because your body is working 6 . Although you may feel as if you are eating more all day long, actually you are not. Not eating breakfast can 7 cause you to overeat, which will put on your weight. 8 breakfast is the first and most important meal of the day, 9 the right food is important. If we choose the wrong food, we may become 10 . In a word, it is necessary for us to have a healthy breakfast. | |||
| ( ) 1. A. Breakfast ( ) 2. A. evening ( ) 3. A. morning ( ) 4. A. with ( ) 5. A. angrier ( ) 6. A. carefully ( ) 7. A. also ( ) 8. A. Though ( ) 9. A. having ( ) 10. A. sad | B. Lunch B. night B. noon B. to B. hungrier B. happily B. too B. So B. choosing B. sick | C. Dinner C. noon C. evening C. of C. sad C. wrongly C. yet C. Since C. taking C. angry | D. Supper D. morning D. night D. for D. boring D. correctly D. as well D. If D. eating D. sorry |