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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: fireemblem13 on March 25, 2006, 11:35:47 AM

Title: Writing Equations
Post by: fireemblem13 on March 25, 2006, 11:35:47 AM
hello, i am new and need help with ipc hwk.
ok, i can balance a given equation when they give u the reactants and the products. but they only give u the reactants and u have to write the the right product. For example,
1. Iron II plus oxygen yields
2. Iron III plus sulfur yields
3. Magnesium plus chlorine yields
...
u don't necessarily need to tell me the answers to 1, 2, and 3. just how to do them
any help is appreciated.
Title: Re:Writing Equations
Post by: Alberto_Kravina on March 25, 2006, 12:01:13 PM
First of all, show us what you have done so far, we're not here to do your homework.... :P

Quote
3. Magnesium plus chlorine yields
Both magnesium and chlorine are pretty reactive, if you combine these elements a stable salt is formed

Quote
1. Iron II plus oxygen yields
Fe(II) can be easily oxidized to Fe(III), try to balance the equation by yourself.
Title: Re:Writing Equations
Post by: fireemblem13 on March 25, 2006, 12:08:00 PM
Ofcourse...
neither do i expect u to.
first of all, the roman numeral is the oxidation number, right?? So
1. Iron II plus oxygen yields ... FeO
2. Iron III plus sulfur yields ... Fe2S3
3. Magnesium plus chlorine yields ... MgCl2
I'm not sure if im doing the right thing.
Title: Re:Writing Equations
Post by: Alberto_Kravina on March 25, 2006, 12:16:36 PM
Quote
1. Iron II plus oxygen yields ... FeO
2. Iron III plus sulfur yields ... Fe2S3
3. Magnesium plus chlorine yields ... MgCl2
Hmmmm...maybe I misunderstood your question :(

1.)What you wrote is the correct formula of Iron(II)oxide, but what I meant was the reaction where Fe2+ is oxidized to Fe3+ with oxygen

2.)Do you mean that Fe3+ reacts with elementar sulfur or do you want to know the formula of Iron(III)sulfide? (Your formula of iron(III)sulfide is correct, by the way... :) )

3.)Correct! Elementar magnesium reacts with chlorine to form Magnesium chloride....
Title: Re:Writing Equations
Post by: fireemblem13 on March 25, 2006, 12:29:28 PM
In that case, how would u write the equation. All i know is that equation is in the form
Reactants -> Product    So, number 1
Fe + O -> FeO
is it that easy and i'm getting worried over nothing . or .
why is the numeral there and where does it go?
Title: Re:Writing Equations
Post by: xiankai on March 25, 2006, 06:42:59 PM
that numeral is to show the oxidation state of the compound, and is written in roman numerals to avoid confusion with ionic charge.

the numeral is not needed when writing equations because its replaced by oxidation state.

as for your reaction, you have to consider the substances that u start out with, not the simplest substance.

hence in this case, an O atom generally does not exist in appreciable quantities long enough for a proper reaction, but instead we use oxygen gas, O2.