level 7
请教下，两道科学问题：-----------------------------------------------------------1.) Name one other food substance which can be used to replace glucose solution and albumen solution.Glucose Solution:Albumen Solution:-----------------------------------------------------------2.) Name one test material which can be used to replace Benedict's solution for testing glucose.
2008年03月23日 14点03分
1
level 7
9；咋了？ ＝ ＝＋10；我也知道…11；唉… 具体意思我懂，可该如何解答？12；在我的国家，科学是英文的… ＝ ＝＋
2008年03月23日 14点03分
17
level 7
13；fat n lipid is which one?glucose or albumen?glucose mean 葡萄糖, n albumen mean egg yolk, isn't?
2008年03月23日 14点03分
22
level 7
21；大叔，嗯… 晓得了... 谢了…哥，什么意思啊？
2008年03月23日 14点03分
25
level 7
大叔，wat mean Fehling? 我在字典找不到... 全题是这样的：----------------------------------------------------------------Food Test:----------------------------------------------------------------1.) Glucosesteps；·put little glucose solution in test tube·add a few drops of Benedict's solution·heat the test tube and its contents in a water bath----------------------------------------------------------------2.) Proteinsteps；·put a little albumen solution in a test tube·add a few drops of Millon's reagent·heat the test tube and its contents in a water bath----------------------------------------------------------------接下来是analysis:----------------------------------------------------------------1.) Name one other food substance which can be used to replace glucose solution and albumen solution in this activity. Glucose Solution: Albumen Solution: ----------------------------------------------------------------2.) Name one test material which can be used to replace Benedict's solution for testing glucose. ----------------------------------------------------------------在这里replace mean 代替...我的程度不好，搞得我有点乱… = =~
2008年03月23日 14点03分
38
level 7
在这里replace mean 代替... 54这句吧… 我都搞乱了…不怎么懂得…
2008年03月23日 14点03分
39
level 7
完全正确，大叔… 敬佩… 所以能代替Benedict's 的是 ”裴林（Fehling）溶液“ 了是吗？
2008年03月23日 15点03分
42
level 7
我搞懂了…这里的 replace mean 代替...
2008年03月23日 15点03分
50
level 7
Fehling's solution is a solution used to differentiate between water soluble aldehyde and ketone functional groups, although ketose monosaccharides (such as fructose) will also test positive, due to conversion to aldoses by the base in the reagent [1]. For this reason, Fehling's reagent is sometimes referred to as a general test for monosaccharides.Fehling's is used to test for aldoses and ketoses, although simpler aldehydes such as formic acid (methanoic acid) also give a positive Fehling's test result, as it does with Tollens' test, Benedict's test. and many more aldehyde tests.To carry out the test The substance to be tested is heated together with Fehling's solution; a red precipitate indicates the presence of an aldehyde. Ketones (except alpha-hydroxy-ketones) do not react. An example for its use is to screen for glucose in urine, thus detecting diabetes. It was developed by German chemist Hermann von Fehling.Fehling's solution is always made just prior to the test. It is comprised of equal parts of the following solutions:69.28 grams copper(II) sulfate pentahydrate dissolved in 1 litre of distilled water (Fehling's solution A) 346 grams Rochelle salt (potassium sodium tartrate tetrahydrate) and 120 grams sodium hydroxide in 1 litre of distilled water (Fehling's Solution B)
2008年03月23日 15点03分
55
level 7
啊… 我认了… 明天问老师去… 唉… 明天考试呐… 要睡了… 88… 还有谢谢… 88了…
2008年03月23日 15点03分
60
level 7
Benedict's reagent (also called Benedict's solution or Benedict's test) is a chemical reagent named after an American chemist, Stanley Rossiter Benedict.[1]Benedict's reagent is used as a test for the presence of all monosaccharides, and generally also reducing sugars. These include glucose, galactose, mannose, lactose and maltose. Even more generally, Benedict's test will detect the presence of aldehydes (except aromatic ones), and alpha-hydroxy-ketones, including those that occur in certain ketoses. Thus, although the ketose fructose is not strictly a reducing sugar, it is an alpha-hydroxy-ketone, and gives a positive test because it is converted to the aldoses glucose and mannose by the base in the reagent.[2].Benedict's reagent can be prepared from sodium carbonate, sodium citrate and copper(II) sulfate.[3] It is often used in place of Fehling's solution.Benedict's reagent contains blue copper(II) ions (Cu2+) which are reduced to copper(I) (Cu+). These are precipitated as red copper(I) oxide which is insoluble in water.
2008年03月23日 15点03分
63
level 7
我现在只有科学这一科… Biologi 还有什么什么的，等高一以后再学，好了，K书去了… 88…
2008年03月23日 15点03分
68