Entropy
This entropy can never decrease.
What is the entropy of the universe?
List 3 differences between the equilibrium dependent equations of ΔGo and ΔGrxn.
ΔGo depends on K and is calculated with a negative sign. ΔGrxn is calculated with Q and is dependent on ΔGo.
Fill in the blanks: During reduction, we ______ electrons. During oxidation, we ______ electrons.
Gain, lose
What is the function of the salt bridge in a galvanic (voltaic) cell?
Allows for the flow of ions to prevent charge build-up.
Write the Nernst Equation:
E = Eo − (0.0591/n)logQ
Which is the correct Equation?
a. ΔSuni=ΔSsys + ΔSsurr
b. ΔSsys = ΔSuni + ΔSsurr
c. ΔSuni = ΔSsys - ΔSsurr
d. ΔSsurr = ΔSuni - ΔSsys
A and/or D.
Determine the signs of ΔSo and ΔHo for the combustion of propane given the following equation:
C_3H_8(g)+5O_2(g)->3CO_2(g)+4H_2O(g)
Why is ΔSo positive and ΔHo negative?
This is the oxidation state of O2. Explain why.
How much is 0 because O2 is an element.
What happens to the mass of the anode and cathode during a redox reaction in a voltaic cell?
Anode loses mass ; Cathode gains mass
Given the half-cell potentials:
Zn²⁺/Zn = –0.76 V Cu²⁺/Cu = +0.34 V
Calculate the standard cell potential (E°cell) for Zn + Cu²⁺ → Zn²⁺ + Cu
+1.10 v
Does absolute molar entropy increase or decrease with molecular complexity? Why?
Molar entropy increases with molecular complexity because energy can have a larger distribution over more molecules/bonds.
When the sign for ΔHo is positive and the sign for ΔSo is negative, this will be the for ΔGo.
What is positive?
These are the steps to balancing a redox reaction in a basic solution. (about 8 steps)
Separate into half reactions,
Balance all elements except oxygen
Balance Oxygens with H2O
Balance Hydrogens with H+
Balance charge with e-
Combine half rxns to cancel e-
Cancel all H+ by adding enough OH- to each side
Reduce H2O molecules
Give the proper line notation for this balanced battery equation:
H2 (g) + Fe3+ (aq) → 2H+ (aq) + Fe2+(aq)
Pt(s) | H2 (g), H+ (aq) || Fe3+ (aq) , Fe2+ (aq) | Pt (s)
If E°cell = +1.25 V, what is the Gibbs free energy change for a reaction involving 2 moles of electrons?
ΔG = –241.2 kJ
A cube of ice is added to some hot water in a rigid, insulated container, which is then sealed. There is no heat exchange with the surroundings. What has happened to the total energy and the total Entropy when the system reaches equilibrium?
Energy remains constant
Entropy increases
Calculate the change in entropy that occurs in the surroundings when acetone (C3H6O) freezes at its melting point (-87.4 degrees C) ΔHfus for acetone is 4.20 kJ/mol.
22.6 J/mol*K
Determine which element is going through reduction/oxidation. CO + I2O5 -> CO2 + I2
Carbon is oxidized, iodine is reduced.
Write the expression for how to find the maximum mass of copper, in grams, that cou1d be plated out by electrolyzing aqueous CuCl2 for 16 hours at a constant current of 3.0 amperes? DO NOT SOLVE (1 faraday = 96,500 coulombs)
(16)(60)(3.0)(96,500)
(63.55)(2)
Cu(s) + 2 Ag+ ---> Cu2+ + 2 Ag(s) If the equilibrium constant for the reaction above is 3.7 x 1015, which of the following correctly describes the standard voltage, E°, and the standard free energy change, deltaG°, for this reaction?
(A) E° is positive and deltaG° is negative.
(B) E° is negative and deltaG° is positive.
(C) E° and deltaG° are both positive.
(D) E° and deltaG° are both negative.
(E) E° and deltaG° are both zero
(A) E° is positive and deltaG° is negative.
N2(g) + 3 H2(g) ---> 2 NH3(g)
The reaction indicated above is thermodynamically favorable at 298 K, but becomes NON-favorable at higher temperatures. What are the signs of each: ΔG, ΔS, and ΔH?
ΔG, ΔH, and ΔS are all negative.
The standard free energy change for the hydrolysis of ATP is -30.5 kJ.
ATP(aq)+H2O(l)→ADP(aq)+Pi(aq)
In a particular cell, the concentrations of ATP, ADP, and Pi are 0.0028 M , 0.0014 M , and 0.0047 M , respectively. Calculate the free energy change for the hydrolysis of ATP under these conditions. (Assume a temperature of 298 K.)
-45.5 kJ or -4.55*104 J
Balance the Following Reaction in Base:
C6H12O6(aq) + VO4 3−(aq) -> CO2(𝑔) + V2+(aq)
(Double Jeopardy)
C6H12O6(aq) + 8VO4 3−(aq) +14H2O(l)-> 6CO2(𝑔) + 8V2+(aq)+40OH-(aq)
Calculate the equilibrium constant K for the following reaction at 25°C:
Fe3+ + e- → Fe2+ , Eo = +0.77 V
1.07 x 1013
The spontaneous reaction that occurs when the cell above operates is:
2Ag+ + Cd(s) ---> 2 Ag(s) + Cd2+
(A) Voltage increases.
(B) Voltage decreases but remains at zero.
(C) Voltage becomes zero and remains at zero.
(D) No change in voltage occurs.
(E) Direction of voltage change cannot be predicted without additional information.
Which of the above occurs for each of the following circumstances?
1. A 50-milliliter sample of a 2-molar Cd(NO3)2 solution is added to the left beaker.
2. The silver electrode is made larger.
3. The salt bridge is replaced by a platinum wire
4. Current is allowed to flow for 5 minutes
B
D
C
B