in the chemical formula for calcium hydroxide, Ca(OH)2, why are the oxygen and hydrogen molecules together in parentheses??
this is just the way my teacher presented it to my class.
2007-09-05 10:42:44 · 6 answers · asked by »-(¯`v´¯)-» xox 2 in Science & Mathematics ➔ Chemistry
usually it means the species within the parenthesis are bonded together into identical "groups" then bonded to the other species which would be the central atom.
for example
Ca(OH)2
is bonded like this....
HO-Ca-OH
the calcium is bonded to two OH's
another example...
(CH3-CO)2O (also known as acetic anhydride)
the last oxygen is the central atom with two CH3-CO's around it like this....
CH3-CO-O-CO-CH3
another example....
Fe(NO3)3
there are three NO's around the central Fe atom...
****update****
the parenthesis have nothing to do with being a "molecule". What they do is indicate "structure". A molecule is an "electrically neutral" stable species containing two or more atoms. OH- is an "ION" not a molecule.
2007-09-05 10:54:50 · answer #1 · answered by Dr W 7 · 1⤊ 0⤋
The reason the OH are together in parentheses is because it is a molecule. The OH has a charge of negative one. So considering the Calcium has a charge of positive two, when the two bond together to make calcium hydroxide, it is saying that for a single calcium ion, there is two hydroxide ions. This is so the molecule is balanced.
From a mathematical stand point, look at it this way:
Calcium = 2+ charge
OH ion = -1 charge
If calcium and a Hydroxide ion are to bond, how many hydroxide ions are needed for the molecules (complete) charge to equal zero?
I hope this helps!!
2007-09-05 10:54:10 · answer #2 · answered by Anonymous · 0⤊ 1⤋
it is a molecule called hydroxide. since it is a molecule, with a -1 charge, and calcium is a molecule with a +2 charge, it takes two hydroxides to balance with the calcium. the parenthesis are there to show the hydroxide is a molecule.
2007-09-05 10:49:03 · answer #3 · answered by Rich 4 · 0⤊ 1⤋
on the freezing component, ice and water coexist. The tendency of the ice to soften is strictly counteracted via the tendency of water to freeze. The chemical potentials of the two levels are equivalent below those situations: In different words, the salt's molecular complexity forces the forged right into a liquid swifter with the aid of thermodynamics... The ice has a tendency to lose it is integrity because of the salt forcing substitute, purely like how salt dissolves into water....
2016-10-10 00:45:28 · answer #4 · answered by Anonymous · 0⤊ 0⤋
(OH) is called hydroxide, and its a polyatomic ion. thats why they're together. you should ask your teacher more about them, or check your textbook
2007-09-05 10:47:55 · answer #5 · answered by Anonymous · 1⤊ 1⤋
because is more simple than HO-Ca-OH
2007-09-05 10:51:19 · answer #6 · answered by catabotis 2 · 1⤊ 0⤋