Equilibrium
Acids and Bases
Electrochemistry
Misc 1
100
At equilibrium, the rates of the forward and reverse reactions are:
Equal
100
Give the formula of sulfurous acid
H2SO3
100
If the oxidation number of a substance decreases, it has undergone:
reduction
100
Which is the better indicator for titrating HCl with NH3? Phenolphthalein (color change pH 8~9) or methyl orange (color change pH 3~4)?
Methyl orange
200
If temperature is increased for an exothermic reaction, the value of Keq is expected to
Decrease
200
Consider the image below and determine whether the acid being titrated is weak or strong, and monoprotic, diprotic, or triprotic
weak, diprotic acid
200
Which of the following is a redox reaction?
A: 3 Cl2(g) + 2 Fe(s) --> 2 FeCl3(s)
B: HCl(aq) + NaOH(aq) --> H2O(l) + NaCl(aq)
A only
200
Which way would the equilibrium below shift if additional PbSO4 was added?
PbSO4(s) ⇄ Pb+2(aq) + SO4-2(aq)
There would be no shift.
300
Consider the equilibrium below:
2SO3(g) ⇌ S(s) + 3O2(g)
Give the equilibrium expression for the reaction:
Keq= [O2]3/[SO3]2
300
Calculate the pH of a 0.0056M solution of NaOH
pH = 14-pOH = 11.75
300
Which electrode does oxidation occur at?
The anode
300
Determine the E°cell for the reaction below:
Ca(s) + 2H+(aq) --> Ca(s) + H2(g)
E°cell = E°ox + E°red = 2.87V + 0V = +2.87V
400
Consider the reaction below:
A(aq) --> 2B(aq) Keq = 151
A reaction mixture has [A] =0.0550M and [B]=1.80M. Which way would the reaction be expected to shift?
Q<K, so reaction will shift to products.
400
Determine the concentration of an HCl solution given that 41.55mL of HCl is needed to titration 12.65mL of 0.998M Ca(OH)2.
[HCl] = 0.606M
400
Balance the following half reaction:
ClO4-(aq) + H+(aq) --> H2O(l) + Cl-(aq)
ClO4-(aq) + 8H+(aq) + 8e- --> 4H2O(l) + Cl-(aq)
400
Explain why Fe(OH)3, Ksp = 2.8*10-39, is less soluble in a pH 10 solution as compared to a pH 7 solution.
Common ion effect. A pH 10 solution has [OH-]=1.0*10-4M while a pH 7 solution has a [OH-]=1.0*10-7M
500
Calculate the [Pb3(PO4)2] in a saturated solution given Ksp of lead(II) phosphate = 9.9*10-55
[Pb3(PO4)2] = 6.2*10-12M
500
Determine the Ka of HCN given a 0.500M solution of HCN has a pH of 4.81
Ka = (10-4.81)2/(0.500M-10-4.81) = 4.8*10-10
500
What is the overall reaction that would occur if a solution of KF was electrolyzed with a 9V battery?
2H2O(l) --> 2H2(g) + O2(g)
500
Consider the values of Ka given, determine which side should dominate at equilibrium and explain your reasoning
HCO3-1: 4.7*10−11
HPO4-2: 4.8*10−13
HCO3-1(aq) + PO4-3(aq) ⇄ HPO4-2(aq) + CO3-2(aq)
Products. The weaker acid/base pair should dominate at equilibrium