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Technoratigeneral basic help
Submitted by Anonymous on 19 November 2006 - 3:59am.
I have started a chemistry to do some schooling upgrade, I have taken my gr 11 chem (a long time ago) and forget half of it I really need help. I can work through problems as long as the course guide shows me an example and I have found that I am fairly proficient at this....However there arent always examples and this is where Im at:
I can figure out the basics behind double reaction equations but I cant figure out why the molecular formula is the way it is ie: O2 (I know really basic but it has me boggled)
And I was wondering if you could help me with this:
zinc+mercurous nitrate----->
I got:
2Zn + Hg2(NO3)2-->Hg2 + Zn2(NO3)2
thanx for all your help and suggestions.....
A brief introduction to
A brief introduction to chemical equations:
We have a number of conventional practices that we often take for granted but are essential for understanding chemical reactions:
We often (but not always) use chemical symbols for the elements: The first letter of the symbol is upper case and a second (or rarely 3rd) letter is lower case.
For simplicity we assume the formula for an element is a single atom unless we know differently. Some elements are diatomic (H, N, O, and the halogens which should be memorized); these are indicated with a trailing subscript such as H2.
In compounds (substances in which elements combine in simple set ratios), the ratio is indicated by trailing subscripts such as H2O. Note that if a trailing subscript is missing like after the O, the subscript is an assumed ONE: water has 2 Hydrogen for every 1 Oxygen. Students new to chemistry typically learn a set of rules which help predict correct formulae. But originally chemists took over 5 decades to determine the correct formulae for the simplest compounds. So the process is not as simple as it may look. Now days an understanding of chemical bonding will also help predict a likely correct formula. Don't except to quickly be able to predict all chemical formulae correctly. Generally such understanding improves over one's LIFETIME!
dave trapp
www.SequimScience.com
There is no Hg2; that is
There is no Hg2; that is mercury is not a diatomic molecule. The equation should be
2Zn + Hg2(NO3)2 > 2Hg + 2Zn(NO3). Whether molecules are monatomic or diatomic is partly empirical, what is observed. Chemistry is basically the manipulation of electrons. Hydrogen has one proton with a positive charge which seeks to be balanced by a single electron's negative charge to produce an electrically neutral atom, but hydrogen comes with a 1s orbital that ideally accomodates 2 electrons; by joining forces, each hydrogen atom in H2 gets the illusion of having 2 electrons but does not suffer from an unbalanced charge.
The inert gasses and metals are generally monatomic; the reactive gasses and halogens are diatomic; phosphorus is tetratomic (P4) and sulfur is octatomic (S8).
Oops! The equation should be
Oops!
The equation should be
Zn + Hg2(NO3)2 > 2Hg + Zn(NO3)2. Zn is bivalent.