CHEM 150
Assignment #5
(Due Thursday, Nov. 28th)
22 total points
1) Write equilibrium constants for each of the following reactions:
a. 3O2(g)  2O3(g)
1 point
b. PCl5(s)  PCl3(l) + Cl2(g)
1 point
c. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
1 point
2) Write a balanced equation for the totally gaseous equilibrium that would lead to the following equilibrium
constant expression:
4H2(g) + CS2(g)  CH4(g) + 2H2S(g)
1 point for formulas on right side, 1 point for correct coefficients, 1 point for
showing states as all gaseous.
3) For the reaction
C6H6(g) + 3H2(g)  C6H12(g) + heat
determine in what direction the equilibrium will be shifted by each of the following changes:
a. Decreasing the concentration of H2
shifts to left (reactant side) 1
b. Increasing the concentration of C6H6
shifts to right (product side) 1
c. Decreasing the temperature
shifts to right (product side) 1
d. Increasing the pressure by decreasing the container volume
shifts to right (product side) 1
4) How many acidic and non-acidic hydrogens are present in each of the following formulas?
a) H2CO3
2 acidic, 0 non-acidic 2
b) H2C3H2O4 2 acidic, 2 non-acidic 2
c) NH3
0 acidic, 3 non-acidic 2
d) HC3H5O2 1 acidic, 5 non-acidic 2
5) Write the acid ionization constant (called Ka, determined like Keq) for each of the following weak acids:
a. HCN
HCN(aq) + H2O(l)  H3O+(aq) + CN-(aq)
1 point
b. HC6H7O6
HC6H7O6(aq) + H2O(l)  H3O+(aq) + C6H7O6-(aq)
1 point
6) Oxaloacetic acid, structure shown below, is produced in metabolic reactions. Would you expect oxaloacetic acid
to be mon-, di-, tri-, or tetraprotic? Why?
Would be expected to be a diprotic acid. C-H bonds aren’t polar and in order for a base to remove the H as H+, it
needs to be part of a polar bond. This must be true in order for the electron pair on the base (e.g. H2O) to
attract H+ from the acid. 1 point for diprotic, 1 point for explanation.