During the O Level Chemistry’s Mole Calculation Mastery Workshop over the last weekend, i noticed to many students do not know how to obtain an Ionic Equations when given a question that has information based on word equation.
In order to benefit more students, especially those avid readers and learners (both locally and overseas), let me share with you the simple 7 steps that are required for you to obtain the Ionic Equation.
Step 1: Write down the Chemical Formulae of reactant & products.
Step 2: Check the number of atoms of each element on both sides.
Step 3: Balance the Equation.
Step 4: Add the State Symbol
Step5: Identify Ionic Compounds/Substances that are soluble in water & split into ions
Step 6: Identify Spectator Ion(s) from equation
Step 7: Cancel out the Spectator Ions & write final Ionic Equation
Let’s take an example to dicuss:
Consider this example:
“Sodium Chloride solution are added to Silver Nitrate solution to form 2 products, a soluble Sodium Nitrate Solution and a insoluble Silver Chloride precipitate. Determine the Ionic Equation and the Spectator Ion(s).”
Working:
Balanced Chemical Equation:
NaCl(aq) + AgNO3(aq) –> AgCl(s) + NaNO3(aq)
Splitting of ions:
Na+(aq) + Cl-(aq) + Ag+(aq) + NO3-(aq) –> AgCl(s) + Na+(aq) + NO3-(aq)
Cancellation of Spectator Ions (appear on both LHS and RHS):
Na+(aq) + Cl- (aq) + Ag+(aq) + NO3-(aq) –> AgCl (s) + Na+(aq) + NO3-(aq)
Species that are left over will make up the Ionic Equation:
Cl- (aq) + Ag+ (aq) –> AgCl (s) ———————– Final Ionic Equation!
Spectator Ions are: NO3-(aq) & Na+(aq)
PS: Let us know how you find about the strategy shown above. Do drop us a comment directly below this post.
can i ask, how do you know which of the following was Spectator Ions and which was not?
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Those which you canceled out are consider as Spectator ions. They have not taken part in any chemical reactions. =)
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Hi. I am glad both of you discussed on this matter. Tan is correct about the Spectator Ions.
Keep up the good work!
Cheers
Sean
Master Trainer
http://www.SimpleChemConcepts.com
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how about in the following reaction… can someone pls help me identify the spectator ions in the following neutralisation reaction
NaOH + HCl —-> NaCl + H2O
thanks!!
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sean Reply:
September 8th, 2008 at 12:50 pm
Hi Sherry,
The above chemical equation is Neutralisation Reaction.
As such, the standard Ionic Equation is H+ + OH- –> H20.
Hope this helps.
Btw, where are you from? Country and which educational system do you follow?
Rgds
Sean
Master Trainer
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usman Reply:
March 28th, 2009 at 2:31 am
spectator ions are those which remain same on the same side of the equation
here main reacton is in between H+ and OH- so spectator ions would be Na+ and Cl-!
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one more question… can we say that they are not taking part in the reaction???
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sean Reply:
September 8th, 2008 at 12:50 pm
In a way, yes..you can say that for Spectator Ions.
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in fact as far as conditions are favourable for the neutralization reaction only you can say they r not reacting but in away certainly they will make salt
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hi am kind of getting the whole spector thing wat am not getting is the forming of the ionic equation.i really need some help as soon as possible am about to do my end of year exam the first 2 weeks of next month.
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oh and wat will be the ionic equation between CUO+H2SO4.
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sean Reply:
October 31st, 2009 at 11:48 pm
Can you write down the Balanced Chemical Equation and their State Symbols HERE?
I will walk you through step-by-step once i have the above from you.
Look forward to hearing from you.
Cheers!
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hey am struggling in my chem class with this ionic equation thing and i need some help as soon as possible.however i think i get this whole spector thing.plz reply.sos
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sean Reply:
October 31st, 2009 at 11:47 pm
Hi Shenel,
This is not that difficult. In fact it is very easy if you follow the steps and sequence above.
All you need is more questions to practice in order to gain the confidence.
You can master this just like many of our students that comes for our workshops and classes.
Cheers!
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Hi! I was surfing and found your blog post… nice! I love your blog.
Cheers! Sandra. R.
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sean Reply:
October 31st, 2009 at 11:43 pm
Thanks for the support and encouragement.
Feel free to drop by to discuss questions or comment on our blogposts.
Cheers!
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hi i was wondering whether there was a, “cheat” way of doing the ionic equations..
what i mean by that is whether there’s a way that will ensure i get every ionic equ. question right..
for me right now.. its a 50/50 chance game
hope you can help mr. sean
cheerz
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sean Reply:
October 31st, 2009 at 11:45 pm
Hi Angi,
There are no cheat ways. Important thing is to understand and memorise the Table of Solubility of Common Salts.
After which, you need to follow the steps and sequence as stated above.
It is actually very easy to do so. You need to practice to gain the confidence of doing it.
Hope this helps.
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hi im really loving the method you used in your example
i was wondering whether you could post up some more examples.. so that all of US get the hang of it!
maybe something with hydrochloric acid (example from my book)
im currently doing AS chemistry in the uk. Edexcel board.
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sean Reply:
October 31st, 2009 at 11:51 pm
Hi Angi,
Why not you write me the Balanced Chemical Equations for the reaction below, including their state symbols?
A) Magnesium Oxide + Hydrochloric Acid
&
B) Sodium Hydroxide + Hydrochloric Acid
PS: You can propose to me their Ionic Equations and Spectator Ions also. I will check for you.
Look forward to hearing from you.
Cheers!
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i dont understand how silver became a positive ion
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sean Reply:
October 31st, 2009 at 11:52 pm
Silver is a Metal and will lose electrons to form Positive Ion. In this case, it will achieve noble gas configurations.
Hope this helps.
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I GET ITTTTTT!! thanks a lot this makes it easier, except, do we have to learn the solubility rules in order to figure out which ions split in water?
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sean Reply:
October 31st, 2009 at 11:53 pm
Absolutely YES! Please remember the table to solubility of common salts. Chemistry students should know it well as it is related to many other chemistry topics.
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Sir Sean,
i wanted to ask, how do we know, we have to do titration or add excess while obtaining the salt of BaSO4 .. please urgent help required. thanks
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sean Reply:
May 6th, 2010 at 12:24 am
Titration only for SPA salts preparation.
SPA = Sodium, Potassium and Ammonium Salts.
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[...] 7 Steps-Strategy to write the Ionic Equation & Spectator Ion [...]
Hi,
I just wanted to know if an element changes its state symbol during the reaction then is it still a spectator ion? My head says no because that means that it has taken part during the reaction but I am not 100% sure, and I’d just like to check.
Thanks!
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sean Reply:
May 6th, 2010 at 12:26 am
Spectator Ion is in AQUEOUS STATE. Check out the example above and see how we determine the Spectator Ion(s).
Hope this helps. Think about it.
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hey,what about those type of equations that have only one aqueous compound? like H2SO4 + CaCO3 = CaSO4 + H2O + CO2, whereby only sulfuric acid is in aqueous state here, calcium carbonate and calcium sulfate both is solid
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Very helpful, thanks
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Hi, I am still confused on how to figure out which parts of the original equation will break up and which to keep together. Can you help please
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Step 4, add the state symbol…
How do you know what state each are in???
Like which one is the solid?
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