Entropy/Enthalpy
A reaction with a positive ΔS and negative ΔH is likely to be ___ at any temperature.
Forward or spontaneous
This happens to electrons during oxidation.
loss
Which animal can sleep standing up and also lying down?
a horse
Reduction occurs here.
cathode
This is the sign of a favorable ΔG° reaction.
negative
A reaction has ΔH = −50 kJ/mol and ΔS = −100 J/mol·K. What is the temperature for the reaction to be spontaneous.
T<500 K
If a reaction produces more gas molecules than it consumes, ΔS of the system is usually ___
positive
This is the charge of Oxygen in a Peroxide.
-1
What is the only letter that does not appear in any U.S. state name?
Q
These move towards the anode.
anions
Negative ΔH°and negative ΔS° would be favorable at these temperatures.
low temperatures
In a 50 g water sample heated from 25°C to 75°C, this formula calculates the heat absorbed.
q = mcΔT
ΔH = +25 kJ/mol, ΔS = +50 J/mol·K. At what temperature in Kelvin will ΔG = 0?
T = ΔH/ΔS = 500 K
These are the oxidation numbers for H₃PO₄.
1, 5, and -2
What is the chemical in your body that makes you feel happy?
dopamine
The purpose of this part of a galvanic cell is to maintain electrical neutrality.
salt bridge
For K > 1, ΔG° is ___
negative
If 2.0A flows for 10s, the total charge passed is calculated as:
20C
Al (s) + HCl (aq) → AlCl₃ (s) + H₂ (g)
Substance ΔH°𝑓 (kj/mol)
Al 0
HCl -167.2
AlCl₃ -705.6
H₂ 0
The enthalpy of formation for the reaction is
-408 kJ/mol (balance equation)
The half reaction for S becomes S-² is this.
S + 2e- → S-²
Which planet spins on its side?
Uranus
What is the cell potential of this reaction?
Half-Reaction E° (V)
Cu2+ (aq) + e- → Cu+ (aq) 0.16
Au3+ (aq) + 3e- → Au (s) 1.50
1.34V
Solve for K if ΔG° = −30.0 kJ/mol at 298 K. (R = 8.314 J/mol·K)
K ≈ 1.8 × 10⁵
A galvanic cell has E°cell = 1.10 V, and 2 moles of electrons are transferred. Calculate ΔG°
−212 kJ
The ΔH of the following reaction NH4Cl → NH3 + HCl is
N2 + 3H2 → 2NH3 ΔH = -91.2 kJ
H2 + Cl2 → 2 HCl ΔH = -184.6 kJ
N2 + 4H2 + Cl2 → 2NH4Cl ΔH = -618.8 kJ
171.5 kJ
Write the oxidation and reduction half reactions for this equation and then the balanced redox equation
Al + Fe₃N₂ → AlN + Fe
2Al → 2Al3+ + 6e-
3Fe2+ + 6e- → 3Fe
2Al + 3Fe2+ → 2Al3+ + 3Fe
Which element is named after the creator of the periodic table?
Mendelevium
Calculating the mass of aluminum produced in 1.00 hour by the electrolysis of molten AlCl₃ if the electrical current is 10.0 A will produce this.
3.36g Al
N₂ (g) + 3F₂ (g) → 2NF₃ (g)
ΔH° = -264 kJ/mol; ΔS° = -278 J/K mol
At 298° K, the ΔG° of this reaction is.
-181 kJ/mol?
During electrolysis, 1.0A flows for 5.0 × 10⁴ s. In a reaction where 3 electrons are needed per mole of product, how many moles of product form?
Step 1: q=I⋅t=1.0*5.0×104=5.0×104 C
Step 2: Moles of electrons = (5.0×104)/96500≈0.518 mol e⁻
Step 3: Moles of product = 0.518 / 3
≈ 0.173 mol