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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: catmoongirl on May 15, 2005, 11:45:22 AM

Title: Understanding how to write equations
Post by: catmoongirl on May 15, 2005, 11:45:22 AM
Okay, so I get how to balance chemical equations and such, the thing I don't get is how to write them from words. For example,
Potassium metal will react with bromine gas to yield solid potassium bromide.
For an answer, the only thing I could think to write would be.
K + Br2 ---> KBr2
I think I may be wrong, so could someone please help explain translating written chemical equations into the actual thing?
Title: Re:Understanding how to write equations
Post by: GCT on May 15, 2005, 02:07:05 PM
2K(s)+Br2(g) --->2KBr(s)
Title: Re:Understanding how to write equations
Post by: catmoongirl on May 15, 2005, 03:01:14 PM
I know the answer...I just don't know how to get to it...I dunno how I'm supposed to know what subscripts to use and how many of each element I put in.
Title: Re:Understanding how to write equations
Post by: GCT on May 15, 2005, 03:04:39 PM
I know the answer...I just don't know how to get to it...I dunno how I'm supposed to know what subscripts to use and how many of each element I put in.

well, the subscript aspect is pretty simple, you should become familiar with it's notations.  As you go along in chemistry understanding equations will become easier, you shouldn't expect to learn it all at once.
Title: Re:Understanding how to write equations
Post by: Donaldson Tan on May 15, 2005, 06:16:38 PM
you must know the valency of your substituent elements. generally, group 1 exhibits valency 1+, group 2 valency 2+, group 3 valency 3+, group 4 valency 4+, group 5 valency 3-, group 6 valency 2-, group 7 valency -1. In order to decide the formula of your compound, you have to put them in such a way that the sum of valency is zero. eg. K is +1, Br is -1, so the compound must be KBr. for H is +1, oxygen is -2, then the compound is H2O, This is just the general rule for dealing with electrically neutral compound.
Title: Re:Understanding how to write equations
Post by: VenDiddy on May 15, 2005, 08:07:36 PM
Look this webpage over:
http://www.roomd116.com/reaction%20notes.htm (http://www.roomd116.com/reaction%20notes.htm)
I found it helpful, just look over all the different types of reactions and their examples.