Directions:Question 20 and 2l refer to the following experiment:Three different pairs of metal wires are placed separately in petri dishes (as shown in the diagram below) containing a mixture of gelatin,rust indicator and phenolphthalein solution.第

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Directions:Question20and2lrefertothefollowingexperiment:Threedifferentpairsofmetalwiresareplacedsepa

Directions:Question 20 and 2l refer to the following experiment:Three different pairs of metal wires are placed separately in petri dishes (as shown in the diagram below) containing a mixture of gelatin,rust indicator and phenolphthalein solution.第
Directions:Question 20 and 2l refer to the following experiment:
Three different pairs of metal wires are placed separately in petri dishes (as shown in
the diagram below) containing a mixture of gelatin,rust indicator and
phenolphthalein solution.
第一个碟子是Fe 和Mg
第二个是Fe和Cu
第三个是Fe和Fe
21.In Dish II,which of the following colours will develop around the iron wire and the copper
wire?
iron wire copper wire
A.pink blue
B.blue pink
C.pink no colour
D.blue no colour

Directions:Question 20 and 2l refer to the following experiment:Three different pairs of metal wires are placed separately in petri dishes (as shown in the diagram below) containing a mixture of gelatin,rust indicator and phenolphthalein solution.第
rust indicator,是铁锈指示剂,会与溶液中的Fe2+反应呈蓝色,所以铁丝上是蓝色
由于电子转移,在铜丝附近会生成OH-,遇酚酞呈粉色
所以选A

答案真是B？ 这是一个原电池反应
cu变为离子使溶液变蓝，fe电极上析出H2使PH上升，酚酞变粉红但这不符合常理
应该是Fe变成离子而溶液无色，Cu电极PH上升酚酞变红

Question Question question Question question Directions是什么意思 directions 翻译 directions for 英语12.There are usually at least two ____of looking at every question.12.There are usually at least two ____of looking at every question.a.means b.directions c.views d.ways为什么 Directions:Question 20 and 2l refer to the following experiment:Three different pairs of metal wires are placed separately in petri dishes (as shown in the diagram below) containing a mixture of gelatin,rust indicator and phenolphthalein solution.第 计算机专业英语求解?Directions:Read the following passage and choose the best answers to each question.（阅读下文选择最佳答案）.Everybody has an opinion about telecommuting（远程办公）.“It won’t work in most jobs”,“I 英语翻译Siri,whose voice do you have?The question has intrigued millions of Apple iPhone and iPad fans,who use the devices' voice-activated personal assistant for help with everything from finding restaurants and directions to organizing their da These are usually at least two ________ of looking at every question.(Unit3-10)A.means B.directions C.views D.ways为什么选D不选C?其它选项用在这里又是什么意思呢? follow one's directions approach from opposite directions in all directions是什么意思 follow these directions是什么意思? 翻译：give directions