Net Ionic Equations In many chemical reactions of two or more compounds, ions ar
ID: 484269 • Letter: N
Question
Net Ionic Equations In many chemical reactions of two or more compounds, ions are present in the solution that do not participate in the reaction. These ions, known as spectator ions, can be removed from the chemical equation describing the reaction. A chemical equation that has the spectator ions removed is known as a net ionic equation.
Reactions between ionic compounds often result in the precipitation of an insoluble compound. Spectator ions and precipitation products of a chemical reaction can be predicted by consulting an ionic substance solubility table. Here is one such table:
Rule General trend
1 Most salts containing alkali metal or ammonium (NH4+) cations are soluble.
2 Most salts containing NO3 are soluble.
3 Most salts containing Cl, Br, and I are soluble, except with metals such as Ag+, Pb2+, and Hg22+.
4 SO42 salts with +1 cations and Mg2+ are soluble, but with most +2 cations these salts are insoluble.
5 Most compounds with OH anions and group 1 or 2 cations are soluble. Notable exceptions are Be(OH)2 and Mg(OH)2. Entering chemical equations
Part A) What is the net ionic equation of the reaction of FeCl2 with NaOH?
Express you answer as a chemical equation including phases.
Part B) What is the net ionic equation of the reaction of MgSO4 with Sr(NO3)2?
Express you answer as a chemical equation including phases.
Explanation / Answer
Answer:
Fe2+(aq)+2OH(aq) Fe(OH)2(s)
Explanation:
Step 1. Write the molecular equation for the reaction.
You use the Solubility Rules to determine if any of the products is a solid.
This tells you that Fe(OH)2 is a solid and NaCl is soluble. The molecular equation is then
FeCl2(aq)+2NaOH(aq)Fe(OH)2(s)+2 NaCl(aq)
Step 2. Write the ionic equation.
Iron(II) chloride when dissolved produces Fe2+ ions and Cl ions.
Sodium hydroxide produces Na+ ions and OH ions.
we can not write solids as ions.
The ionic equation is
Fe2+(aq)+2Cl(aq)+2Na+(aq)+2OH(aq)Fe(OH)2(s)+2Na+(aq)+2Cl(aq)
Step 3. Cancel items that appear on each side of the equation (2Cl and 2Na+) to get the net ionic equation.
Fe2+(aq)+2Cl(aq)+2Na+(aq)+2OH(aq)Fe(OH)2(s)+2Na+(aq)+2Cl(aq)
The net ionic equation is
Fe2+(aq)+2OH(aq)Fe(OH)2(s)
MgSO4 and Sr(NO3)2 are both soluble, so the ionic equation would look like this.
Mg+2 + SO4-2 + Sr+2 + 2NO3-1 ---> Mg+2 + 2NO3-2 + SrSO4
SrSO4 is insoluble. Now Mg and 2NO3 are on both sides, so cross them out, the net ionic equation is
Sr^2+(aq)+SO4^2(aq)SrSO4(s)