FREE RESPONSE REVIEW
1. Balance and Classify the following reactions according to combination (CA), decomposition (D),
combustion (CU), single replacement (SR) or double replacement (DR) and then balance the equations.
Reaction
Classification
a. ___Mg(s) + ___ZnCl2(aq) = ___MgCl2(aq) + ___Zn(s)
_____
b. ___AgNO3(aq) + ___CaCl2(aq) = ___AgCl(s) + ___Ca(NO3)2(aq)
_____
c. ___C2H6(g) + ___O2(g) = ___CO2(g) + ___H2O(g)
_____
d. ___Na2O(s) + ___H2O(l) = ___NaOH(aq)
_____
e. ___KClO3(s) = ___KCl(s) + ___O2 (g)
_____
f. ___Al(s) + ___HCl(aq) = ___AlCl3(aq) + ___H2(g)
_____
g. ___C3H6O(g) + ___O2(g) = ___CO2(g) + ___H2O(g)
_____
h. ___Fe(s) + ___O2(g) = ___Fe2O3(s)
_____
i. ___Cl2(aq) + ___KBr(aq) = ___Br2(aq) + ___KCl(aq)
_____
j. ___Ca(NO3)2(aq) + ___K3PO4(aq) = ___Ca3(PO4)2(s) + ___KNO3(aq)
_____
k. ___Ca(HCO3)2(aq) = ___CaCO3(s) + ___H2O(l) + ___CO2(g)
_____
l. ___NaOH(aq) + ___H3PO4(aq) = ___Na3PO4(s) + ___H2O(aq)
_____
2. Complete, balance and classify the reactions below. For aqueous reactions, include a net ionic
equation when appropriate
Reaction
Classification
a. ___NaOH(aq) + ___CuSO4(aq) =
_____
b. ___Mg(s) +
_____
ZnCl2(aq) =
c. ___C4H10(g) + ___O2(g) =
_____
d. ___Pb(NO3)2(aq) + ___K2CrO4(aq) =
_____
e. ___Mg(s) + ___H2SO4(aq) =
_____
f. ___C2H4O(l) + ___O2(g) =
_____
g. ___HNO3(aq) + ___Ba(OH)2(aq)
_____
h. ___HCl(aq) + ___KHCO3(aq) =
_____
i. ___Zn(s) + ___MgCl2(aq) =
_____
3. The molecular weight of a monoprotic acid HX was to be determined. A sample of 15.126 grams of HX
was dissolved in distilled water and the volume brought to exactly 250.00 millilitres in a volumetric
flask. Several 50.00 millilitre portions of this solution were titrated against NaOH solution, requiring an
average of 38.21 millilitres of NaOH.
The NaOH solution was standardized against HC2O4 . 2H2O oxalic acid dihydrate(molecular weight:
126.066 gram mol-1). The volume of NaOH solution required to neutralize 1.2596 grams of oxalic acid
dihydrate was 41.24 millilitres.
(a)
Calculate the molarity of the NaOH solution.
(b)
Calculate the number of moles of HX in a 50.00 millilitre portion used for titration.
(c)
Calculate the molecular weight of HX.
(d)
Discuss the effect of the calculated molecular weight of HX if the sample of oxalic acid dihydrate
contained a nonacidic impurity.