What is the difference between a compound and a molecule?

In summary, molecules are formed when two or more atoms join together chemically and compounds are molecules that contain at least two different types of atoms. All compounds are molecules but not all molecules are compounds. Compounds are substances made up of elements and can be broken down into them, while molecules are made of atoms. The smallest piece of an element is an atom and the smallest piece of a compound is a molecule. According to Giancoli's text, an H2O molecule by itself is not a compound, but a collection of H2O molecules is a compound. This is similar to how a gold atom by itself is not an element, but a collection of gold atoms is an element. Overall, it is not important to lose sleep over
  • #1
kjamha
98
1
I have read several definitions that basically say a molecule is formed when two or more atoms join together chemically. And a compound is a molecule that contains at least two different types of atoms. All compounds are molecules but not all molecules are compounds.

Examples of molecules include H2O, O2, O3 and examples of compounds include NaCl, H2O.

Giancoli's text states that "compounds are substances made up of elements, and can be broken down into them; examples include carbon dioxide and water. The smallest piece of an element is an atom; the smallest piece of a compound is a molecule. Molecules are made of atoms."

I would interpret Giancoli's definition to say that an H2O molecule by itself is not a compound - but a collection of H2O molecules IS a compound. The same way that a gold atom by itself is not an element, but a collection of gold atoms is an element.

Is my interpretation way off?
 
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  • #2
That sounds ok to me but, really, why lose sleep over that? I cannot think of a situation where the could be confusion generated and that's the only time that terminology or classification may be important.
 
  • #3
kjamha said:
Giancoli's text states that "compounds are substances made up of elements, and can be broken down into them; examples include carbon dioxide and water. The smallest piece of an element is an atom; the smallest piece of a compound is a molecule. Molecules are made of atoms."

I would interpret Giancoli's definition to say that an H2O molecule by itself is not a compound - but a collection of H2O molecules IS a compound. The same way that a gold atom by itself is not an element, but a collection of gold atoms is an element.

Is my interpretation way off?

That's not what the text intended to imply. A gold atom by itself is indeed an element and one molecule of water is a compound. These are the smallest either one can be reduced and still remain an element and a compound, respectively.
 

1. What is the definition of a compound?

A compound is a substance that is made up of two or more different elements chemically bonded together in a fixed ratio.

2. How is a molecule different from a compound?

A molecule is a combination of two or more atoms held together by chemical bonds. A compound is a type of molecule, but it specifically refers to a substance made up of different elements.

3. Can a compound be made up of just one type of atom?

No, a compound must be made up of at least two different elements.

4. Are all compounds considered molecules?

Yes, all compounds can be classified as molecules, but not all molecules are compounds. For example, diatomic molecules like oxygen (O2) and nitrogen (N2) are not compounds because they are made up of only one type of element.

5. How are compounds and molecules represented in chemical formulas?

Compounds are represented by using the chemical symbols of the elements and subscripts to indicate the number of atoms of each element present. Molecules are represented in a similar way, but with only one type of element present. For example, the compound water (H2O) is made up of two hydrogen atoms and one oxygen atom, while the molecule oxygen gas (O2) is made up of two oxygen atoms bonded together.

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