Question

How can I find chemical formula of a mixture?

Answer 1

That's a tricky question. What information are you given?

Answer 2

We hypothesize that I've got a juice. I want to discover chemical formula of this juice. How I can do it?

Answer 3

A juice is made of highly complex organic molecules, so I'm not sure how you'd go about determining its exact chemical formula (for example, Vitamin A is 2E,4E,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol (Retinol), which sure doesn't roll off the tongue!)

It might be possible to guess at what's in it by doing some experiments, however:

-Boiling off the water and looking at what remains
-Seeing if the juice is acidic, basic, or neutral via pH test strips
-Letting the juice sit and seeing if it anything separates from the mixture
-Looking up the color, odor, and so forth of the juice in databases

Answer 4

Ok, thanks. I'll try your solution. If I'd want discover chemical formula of color knowing the components?

Answer 5

I'm a bit confused- are you looking for the chemical formula of the mixture with knowledge of its components? Mixtures don't involve chemical reactions, so nothing about the components should change.

Answer 6

Excuse me, I haven't explained well. For example: juice contains water,vitamin C,dyes and other components. If I examine a drop of this juice, what chemical formula do I find?
(H2O,C6H8O6...)

Answer 7

Water is trivial to detect, so that doesn't need an explanation.

Vitamin C is water soluble, meaning that you can't observe it in solution. Finding it would require some sort of chemical reaction.

You could probably verify the types of dyes in solution by placing paper in the juice. It would be drawn up the paper by the capillary effect (if I'm not mistaken), making the different dyes plainly visible.

Answer 8

Ok. Last question (maybe). I've got some dirt and I want to plant some mais. How can I discover % of nitrogen in the dirt?

Answer 9

A mass spectrometer is the best way to do this, since it can measure the exact amounts of each element in the sample. Of course, since mass spectrometers aren't exactly easy to come across, you can't always do this.

Burning the soil would provide some indication of its composition, although you'd still need a way to measure the amounts of each gas.

You can also use chemicals to extract the nitrite, nitrate, and ammonia from the soil. I'm not very familiar with this, however.

This site looks promising: http://bcn.boulder.co.us/basin/data/BACT/info/NO3+NO2.html

I'd have given it a thorough read, but I've gotta' finish my bio review for finals! Good luck!