Re: Basic Chemistry Stuff
Quote:
Originally Posted by kingwinner
1) Are the terms "element" and "atom" interchangeable? If not, why not?
No. An element is a discrete species of an atom and would have specific characters. An atom is the description of the basic structure of an element. The nature of the atom (number of electrons, protons, etc.) define the type of element it is.
Quote:
Originally Posted by kingwinner
2) Do the terms "substance" and "matter" mean exactly the same thing?
I would think so. The usage of one or the other would depend largely on context. You wouldn't say "a matter" comprised of... but you could say "a substance comprised of..." The word 'matter' would likely be used in contexts of mass whereas 'substance' would be used in contexts of characteristics.
Quote:
Originally Posted by kingwinner
3) "Two of the eight common elements in the earth's crust are oxygen (O) and silicon (Si)"
Why is oxygen expressed as O, instead of O2, in both the quote and diagram? Does that mean single O atom exist naturally in the crust?
O<sub>2</sub> is a diatomic molecule of oxygen, whereas O is the element/atom that is known as oxygen. The graph represents oxygen as "O" because not all the oxygen on the Earth is part of diatomic molecules. A good portion of it is tied up in other molecules (H<sub>2</sub>O, for instance).
Quote:
Originally Posted by kingwinner
4) Compound: a substance that results when the atoms of two or more elements are chemically combined
This is the definition of a "compound" from my text book and it's the same as all sources in the internet. According to the definition of a compound, O2 and N2 are not compounds, than what are they? elements?
They're diatomic molecules, or two atoms, of a single element. NO<sub>2</sub>, however, is a compound.
I'm sure someone else could expand upon my words... I'm going completely off of memory. I had a dynamite chem professor and learned a lot, but I really didn't have a knack for it.