[noat]

Hi!

How can a substance be both organic and inorganic?

[sjb]

What definitions are you using, and do you have any compounds in mind?

[noat]

Inorganic: substances that we find in the lifeless nature.
Organic: Substances that we find in the living nature or substances that come from dead plants.

I have to choose between:
NH4OH
C3H7OH
Ca3(PO4)2
H2CO3
Fe2O3
KCl
HCOOH
HCHO
N2O5
CH3COCH3
AgNO3
Al2(SO4)3
C4H10
C6H6
HNO3
CH2=CH2
H2O

[Arkcon]

Inorganic: substances that we find in the lifeless nature.
Organic: Substances that we find in the living nature or substances that come from dead plants.

Those are definitions, but they are poor ones, by modern thinking.  However, if that's what yuou have to work with, we can do our best, if only to show how poor those definitions are.

I have to choose between:

I'm going to trim your list a bit, highlighting some interesting ones, you might want to investigate each one, splitting the list into "inorganic", "organic", and "maybe both" and "I don't know."  Or maybe better yet, "Completely organic" and "why is a rock even here?"

NH4OH

Research the history of this one, its useful for you to understand how your definitions aren't the best.

C3H7OH

Look up compounds of carbon, they can link in multiple ways, and have different properties.  Empirical formulas, in this case, aren't clear.  See if this helps your definitions.

H2CO3

Look up this one.  What is it?  How does it compare to both your definitions?  WHere does it come from, how do we get it, and what reactions does it undergo?

HCOOH
HCHO
CH3COCH3
C4H10
C6H6

Again, as above, these can mean anything.  Look up the names, what do they mean.

CH2=CH2

Now this one is clear, because of how it specifies the bonding.  See if this helps you make your lists.

The instructor gave you this list to see where your knowledge would take you with it.  Show that sort of work.

[noat]

Inorganic: substances that we find in the lifeless nature.
Organic: Substances that we find in the living nature or substances that come from dead plants.

Those are definitions, but they are poor ones, by modern thinking.  However, if that's what yuou have to work with, we can do our best, if only to show how poor those definitions are.

I have to choose between:

I'm going to trim your list a bit, highlighting some interesting ones, you might want to investigate each one, splitting the list into "inorganic", "organic", and "maybe both" and "I don't know."  Or maybe better yet, "Completely organic" and "why is a rock even here?"

NH4OH

Research the history of this one, its useful for you to understand how your definitions aren't the best.

C3H7OH

Look up compounds of carbon, they can link in multiple ways, and have different properties.  Empirical formulas, in this case, aren't clear.  See if this helps your definitions.

H2CO3

Look up this one.  What is it?  How does it compare to both your definitions?  WHere does it come from, how do we get it, and what reactions does it undergo?

HCOOH
HCHO
CH3COCH3
C4H10
C6H6

Again, as above, these can mean anything.  Look up the names, what do they mean.

CH2=CH2

Now this one is clear, because of how it specifies the bonding.  See if this helps you make your lists.

The instructor gave you this list to see where your knowledge would take you with it.  Show that sort of work.

So I checked all the substances. Most of the organic substances have a C–H bond. But I still don't understand how a substance can be both organic and inorganic.

List I made:

-Organic:
C3H7OH
HCOOH
CH3COCH3
HCHO
C4H10
C6H6
CH2=CH2

-Inorganic:
NH4OH
Ca3(PO4)2
H2CO3
Fe2O3
KCl
N2O5
AgNO3
Al2(SO4)3
HNO3
H2O

[wildfyr]

I would posit that by strict modern definitions a compound cannot be both organic and inorganic.

There are to some degree exceptions (because chemistry is hard) but the provenance of a compound has no bearing on whether it is organic or inorganic.

I could harvest ethane and oxygen from the surface of one of Saturn's moons and convert them into sucrose with a large amount of effort. Is this sucrose molecule organic? It never had anything to do with life or plant matter in the previous 3 billion years. But sucrose is a sugar typically derived from plants! Hmm...

Molluscs produce calcium carbonate in cells and excrete it to make shells. Is it organic? It was produced by biological functions.

You see why Arkcon questioned your definitions. Also, I agree with the list you made.

[Arkcon]

You've done a good job, noat:.  (But please don't quote an monster post of mine, along with your own original postings, because that's bad netiquette: it makes the post longer, for no benefit.)  I like how you noticed the modern definition: H₂CO₃, like all carbonates, is inorganic.  We all just decided that, even though, as was said, it may have come from a living thing some time in Earth's history.