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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: kidmo87 on March 07, 2013, 05:53:56 PM

Title: Balancing Chemical Equation
Post by: kidmo87 on March 07, 2013, 05:53:56 PM
Hello everyone. I am stuck on trying to balance chemical equations. I have the answer, but I just don't know how to plug in numbers, because when I look at it, at already looks balanced. The questions is: Write balanced net ionic equation for the precipitation reaction of CaCl2 and Cs3PO4
AB+CD :rarrow: AD+CD
CaCl2 + Cs3PO4  :rarrow: CaPO4 + Cs3Cl2.
and on the homework the answer says:
3CaCl2 + 2Cs3PO4  :rarrow: 6CsCl + Ca3(PO4)2

Honestly, Im horrible at chemistry, but when I look, I don't see how my equation isn't balanced. I would really appreciate some help, thanks.
Title: Re: Balancing Chemical Equation
Post by: Borek on March 07, 2013, 06:06:31 PM
Quote from: kidmo87 on March 07, 2013, 05:53:56 PM
Write balanced net ionic equation for the precipitation reaction of CaCl2 and CsPO4

Is it really asking about CsPO4, or is it asking about cesium phosphate? What is the formula of the cesium phosphate?

The answer you listed is not a net ionic equation.
Title: Re: Balancing Chemical Equation
Post by: kidmo87 on March 07, 2013, 06:15:49 PM
Oh im sorry, its actually CaCl2 and Cs3PO4. And no, it asks like how I wrote it.
Title: Re: Balancing Chemical Equation
Post by: Arkcon on March 07, 2013, 06:58:09 PM
What is the difference between your answer, and the correct one?  Can you see what you did wrong?  Do the products match?  And why not?
Title: Re: Balancing Chemical Equation
Post by: kidmo87 on March 07, 2013, 07:06:49 PM
Honestly, other than them being switched around, but I though it was AB+CD :rarrow: AD+CB.
Like I don't understand why mine is unbalanced for me to start inserting numbers to make them balanced.
Title: Re: Balancing Chemical Equation
Post by: hockey101 on March 07, 2013, 09:10:42 PM
I can see what the problem is....if you look at Cs on the Periodic table its a +1 (i forgot what their called valance electrons maybe?) and Cl is a -1.  So when you do the criss-cross rule, they cancel out since its 1 to 1.  So it should read CsCl.  You do that for all the elements.  For PO4, I believe you have to look in your chem book because its a polyatomic ion.  According to table 9.3 in my book, PO4 reads at a charge of 3-.  So for your Ca and PO4 Ca is a 2+ charge and PO4 is a 3-.  When you do the criss-cross rule, it becomes Ca3(PO4)2.  Then after all that you should be able to start balancing....hope this helps!!
Title: Re: Balancing Chemical Equation
Post by: JGK on March 08, 2013, 01:45:42 PM
forgive me for being a bit puzzled here but is this seriously an "undergraduate level" problem. This is the kind of stuff I was expected to do at age 14 in high school.  ???
Title: Re: Balancing Chemical Equation
Post by: Borek on March 08, 2013, 02:01:20 PM
Quote from: JGK on March 08, 2013, 01:45:42 PM
forgive me for being a bit puzzled here but is this seriously an "undergraduate level" problem. This is the kind of stuff I was expected to do at age 14 in high school.  ???

Good point. Moved.