Chemistry for dummies (me)?

Question

Okay, I did a lab in class, but I'm having a little trouble with answering the questions about the lab... so your help would be much appreciated.

Okay, so first I added NH4OH, AgNO3 and glucose to a test tube.I saw that silver was coating the inside of the test tube, but the question is:

1. *Explain how the presence of glucose allowed this coating to form*

I thought the reaction of NH4OH and AgNo3, would produce NH4NO3 and AgNo3 (a precipitate), but apparently ther's more to it. I just really don't know where to add the C6H12O6 into the equasion. I don't need the equasion, I just need to understand what glucose has to do with it.

And I also have another question....
I added 5ml of Benedict's solution (it detects reducing sugars such as glucose and fructose) to 5 test tubes. THen to each of those 5 test tubes I added 8 drops of 2% glucose solution. I then heated the mixtures for ...

Guaranteed "best answer" to the most helpful answer.

Thanks in advance

(continuation of second question)

I heated the mixtures for 5 minutes, and theyy were all different colors, even though I put the same thing in all of the test tubes...

The question is

"Chances are that each of your five test tubes was identical in appearence, but they may not have been. Suppose they had not all been the same color. Make a bypothesis to account for this.

Answer 1

You're almost right.
AgNO3 + NH4OH -> NH4NO3 + AgOH(s)
but if you keep adding NH4OH, AgOH will dissolve in it
the mixture is called the Tollens reagent.
Tollens reagent is capable of detecting reducing species, in this case: glucose. Remember glucose has -CHO group.
2AgOH + (-CHO) -> 2Ag(s) + H2O + (-COOH)
The glucose is oxidized to form gluconic acid, while AgOH reduced to solid Ag. This solid Ag precipitate in such a way that it forms a silver layer on the test tube, thus this reaction is called "silver mirror reaction".

For the second part, are you sure all the 5 test tubes are in the same initial condition and undergo the same process?
If yes then I really don't know what had happened there. That's a bit weird.

Answer 2

The silver mirror is a test for aldehydes called the Tollens Test for Aldehydes. The glucose was the aldehyde. The glucose is oxidized to an organic acid and the Silver is reduced to metalic silver. See the first reference below:

The results of the Benedict's solution test is a measure of how precise your experimental actions were. The more each act is done "the same" the closer the final results will be (the formation of a red copper compound). If your results were all different then you either did a poor job measuring the reactants or did something different when heating each tube.

Depending upon the concentration of the Cu+2, the final colors can be anything from green to brick-red. See the last sites below:

Answer 3

Orgo is carefully diverse from Gen Chem in my view. there is diverse memorization in Orgo and little or no genuine information required. i could probably say your Orgo grade is larger correlated alongside with your Bio grade than your Gen Chem grade. So in case you probably did properly in Bio, go forward and take Orgo. whether, it extremely is sweet to to circulate over here (in no actual order in any respect): -Thermodynamics (delta H, G, S) -Quantum mechanics (s,p,d,f,sigma,pi orbitals) -VSEPR concept and the linked geometries *** -Formal expenses -Periodic table traits (electronegativity and so on) *** *** greater important than the others