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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: saN on November 16, 2006, 07:54:40 PM

Title: Net Ionic Equations
Post by: saN on November 16, 2006, 07:54:40 PM
For these reactions with acids, I am suppose to write a net ionic equation. I have finished all my other ones, but the one that is stomping me is Sulfuric Acid (H2SO4) and Chromium metal (Cr). I am unsure what the ion part is of the Sulfuric Acid. I know that in the products, there is hydrogen gas produced. Thanks!
Title: Re: Net Ionic Equations
Post by: Borek on November 16, 2006, 07:56:54 PM
It will dissociate giving two H+. Although usually in the solutions - especially more concentrated - only one H+ is removed from the molecule.
Title: Re: Net Ionic Equations
Post by: saN on November 16, 2006, 07:59:52 PM
Therefore, it would be:

2H+(aq) + Cr(s) ==> Cr+2(aq) + H2(g)?
Title: Re: Net Ionic Equations
Post by: saN on November 17, 2006, 04:49:14 PM
Now, I must write total and net ionic equations for the reactions occured. I just wanted to see if my process is correct.

Aluminum in 3M HCl (Would it be the same with 6M HCl?):

Al(s) + 3HCl(aq) => AlCl3(aq) + H2(g)     I know this is totally wrong because it is not balanced, but Al is +3 and Cl is -1, and this is where it stumps me.

Iron in 3M HCl (Would it be the same with 6M HCl?):

Fe(s) + 2HCl(aq) => FeCl2(aq) + H2(g)
Fe(s) + 2H+(aq) => Fe+2(aq) + H2(g)

Iron in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Fe(s) + H2SO4(aq) => FeSO4(aq) + H2(g)
Fe(s) + 2H+(aq) => Fe+2(aq) + H2(g)

Magnesium in 3M HCl (Would it be the same with 6M HCl?):

Mg(s) + 2HCl(aq) => MgCl2(aq) + H2(g)
Mg(s) + 2H+(aq) => Mg+2(aq) + H2(g)

Magnesium in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Mg(s) + H2SO4(aq) => MgSO4(aq) + H2(g)
Mg(s) + 2H+(aq) => Mg+2(aq) + H2(g)

Zinc in 3M HCl (Would it be the same with 6M HCl?):

Zn(s) + 2HCl(aq) => ZnCl2(aq) + H2(g)
Zn(s) + 2H+(aq) => Zn+2(aq) + H2(g)

Zinc in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Zn(s) + H2SO4(aq) => ZnSO4(aq) + H2(g)
Zn(s) + 2H+(aq) => Zn+2(aq) + H2(g)

What kind of reaction is it when a solid changes color (Zinc turns black in Copper Nitrate solution)?
Title: Re: Net Ionic Equations
Post by: saN on November 22, 2006, 03:47:29 AM
Anyone? I just want to see if my equations are correct.
Title: Re: Net Ionic Equations
Post by: AWK on November 22, 2006, 04:34:10 AM
Now, I must write total and net ionic equations for the reactions occured. I just wanted to see if my process is correct.

Aluminum in 3M HCl (Would it be the same with 6M HCl?):

Al(s) + 3HCl(aq) => AlCl3(aq) + H2(g)     I know this is totally wrong because it is not balanced, but Al is +3 and Cl is -1, and this is where it stumps me.

Iron in 3M HCl (Would it be the same with 6M HCl?):

Fe(s) + 2HCl(aq) => FeCl2(aq) + H2(g)
Fe(s) + 2H+(aq) => Fe+2(aq) + H2(g)

Iron in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Fe(s) + H2SO4(aq) => FeSO4(aq) + H2(g)
Fe(s) + 2H+(aq) => Fe+2(aq) + H2(g)

Magnesium in 3M HCl (Would it be the same with 6M HCl?):

Mg(s) + 2HCl(aq) => MgCl2(aq) + H2(g)
Mg(s) + 2H+(aq) => Mg+2(aq) + H2(g)

Magnesium in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Mg(s) + H2SO4(aq) => MgSO4(aq) + H2(g)
Mg(s) + 2H+(aq) => Mg+2(aq) + H2(g)

Zinc in 3M HCl (Would it be the same with 6M HCl?):

Zn(s) + 2HCl(aq) => ZnCl2(aq) + H2(g)
Zn(s) + 2H+(aq) => Zn+2(aq) + H2(g)

Zinc in 3M H2SO4 (Would it be the same with 6M H2SO4?):

Zn(s) + H2SO4(aq) => ZnSO4(aq) + H2(g)
Zn(s) + 2H+(aq) => Zn+2(aq) + H2(g)

What kind of reaction is it when a solid changes color (Zinc turns black in Copper Nitrate solution)?
2Al(s) + 6HCl(aq)
Others are correct
Title: Re: Net Ionic Equations
Post by: Borek on November 22, 2006, 05:02:59 AM
Note: concentrations doesn't matter here. They may play a role in the case of nitric acid.
Title: Re: Net Ionic Equations
Post by: saN on November 22, 2006, 01:36:47 PM
thanks!!
Title: Re: Net Ionic Equations
Post by: saN on November 30, 2006, 04:10:25 PM
Anyone on the "What kind of reaction is it when a solid changes color (Zinc turns black in Copper Nitrate solution)?" question?
Title: Re: Net Ionic Equations
Post by: saN on November 30, 2006, 04:26:59 PM
Is this correct?

Zn(s) + Cu(NO3)2(aq) -> Cu+2(aq) + Zn(NO3)2(s)
Title: Re: Net Ionic Equations
Post by: Borek on November 30, 2006, 04:34:56 PM
Is this correct?

Zn(s) + Cu(NO3)2(aq) -> Cu+2(aq) + Zn(NO3)2(s)

As to the idea - yes. But it is not net ionic.
Title: Re: Net Ionic Equations
Post by: saN on November 30, 2006, 04:50:20 PM
The net ionic would be this:

Zn(s) + 2NO3-(aq) -> Zn(NO3)2(s)

Would the ionic question be this:

Zn(s) + Cu+2(aq) + 2NO3-(aq) -> Cu+2(aq) + Zn(NO3)2(s)

or would the solid in the product be also broken apart?
Title: Re: Net Ionic Equations
Post by: Borek on November 30, 2006, 04:59:15 PM
Oops, I have now realised that you were wrong. Sorry, but your equation was not even OK when it comes to the idea.

Both salts are dissolved so the solid you see is not nitrate, but the thing I have missed is that copper on the right is in the ionic form.

Check reactivity series - Zn vs Cu.
Title: Re: Net Ionic Equations
Post by: saN on November 30, 2006, 05:07:15 PM
I did some searching before and what I got from it is Zinc + Copper Nitrate ---> Copper + Zinc Nitrate. I should've thought of that myself of nitrates being soluble. Now, it bugs me why the zinc solid turned black....
Title: Re: Net Ionic Equations
Post by: saN on November 30, 2006, 05:24:00 PM
Zn(s) + Cu(NO3)2(aq) -> Cu(s) + Zn(NO3)2(aq)
Zn(s) + Cu+2(aq) + 2NO3-(aq) -> Cu(s) + Zn+2(aq) + (NO3)2(aq)
Zn(s) + Cu+2(aq) -> Cu(s) + Zn+2(aq)