(10 points) For each of the following ten combinations of reagents, write a balanced net-ionic equation assuming that 10 drops of the first reagent was combined with 10 drops of the second reagent. Also write your observations for each combination of reagents. Note that each equation will be worth 1 point. See the grading rubric below for more details on the grading. You do not need to use Equation Editor, but you must include proper subscripts, superscripts, and phase labels.
Guidelines for writing reactions:
a. If a solution became cloudy or gel-like or an obvious solid formed, you should indicate that one of the products is a solid with the physical state designator (s).
b. If a solution ONLY changed colors but remained clear, the product is not a solid but is a soluble product. The formulas of these products are harder for you to predict at this point in the year, so you may simply show the reactants on the left side of the arrow (as ions, if appropriate) and on the right side of the arrow write “complex ion.”
c. If a reaction ONLY generates heat, you can assume the reaction is an acid-base reaction. In this case, the nature of the base will determine whether the product is H2O(l) or something else.
d. Read the notes on the second page of the lab procedure in your lab manual. If there was no reaction for a particular combination, you should write the reactants on the left side of the arrow (as ions, if appropriate) and on the right side of the arrow write “no reaction.”
e. It will be helpful for you to remember that a solution of the neutral weak base NH3 always has some NH4+(aq) and OH–(aq) ions in it.
f. For some of the solutions, the identity of the ion reacting will depend on what else it is reacting with. For example, in HCl(aq), sometimes the H+(aq) ion may react and sometimes the Cl–(aq) ion may react instead. Use everything you know about the compounds to help you write the equations.
Grading Rubric for net-ionic equations
-5pts: Correct formulas and products, but no attempt to balance
-3pts: No state labels or very few state labels
-2pts: A couple major, obvious errors
-2pts: No observations
-1pt: A few minor errors or inconsistencies
For numerous major errors or being incomplete more points may be taken off.
a. Ni(NO3)2 and NH3
{Write observation here. Be sure to do this for each of the other 9 reactions also.}
Ni(NO3)2+2NH3=2NO3+Ni(NH3)2
b. Pb(NO3)2 and HCl
c. HNO3 and Na2CO3
d. CuSO4 and NaOH
e. Fe(NO3)3 and HCl
f. HCl and AgC2H3O2
g. Fe(NO3)3 and NH3
h. NaI and HCl
i. NaOH and H2SO4
j. Na2CO3 and BaCl2
k. NaI and H2SO4