During the O Level Chemistry’s Mole Calculation Mastery Workshop over the last weekend, i noticed that many students do not know how to obtain an Ionic Equations when given a question that has information based on word equation. In fact, i always observe this problem whenever a new student joins in my Sec 3 or Sec 4 O-Level Chemistry Tuition Classes.
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.
PPS:
Updates in 2011! I have made a video on Writing Ionic Equations!
View the video at: http://www.simplechemconcepts.com/o-level-chemistry-videos-on-writing-ionic-equations/