<span>Energy definition, as used in chemistry, chemical engineering, and physics.</span>
Answer:
D. Ni²⁺
Explanation:
We know at once that the answer cannot be A or C, because Ni and Cu are already in their lowest oxidation states.
The correct answer must be either B or D.
An electrolytic cell is the opposite of a galvanic cell. In the former, the reaction proceeds spontaneously. In the latter, you must force the reaction to occur.
One strategy to solve this problem is:
- Look up the standard reduction potentials for the half reaction·
- Figure out the spontaneous direction.
- Write the equation in the reverse direction.
1. Standard reduction potentials
E°/V
Cu²⁺ + 2e⁻ ⟶ Cu; 0.3419
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
2. Galvanic Cell
We reverse the direction of the more negative half cell and add.
<u>E°/V
</u>
Ni ⟶ Ni²⁺ + 2e⁻; 0.257
<u>Cu²⁺ + 2e⁻ ⟶ Cu; </u> 0.3419
Ni + Cu²⁺ ⟶ Cu + Ni²⁺; 0.599
This is the spontaneous direction.
Cu²⁺ is reduced to Cu.
3. Electrochemical cell
<u>E°/V</u>
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
<u>Cu ⟶ Cu²⁺ + 2e⁻; </u> <u>-0.3419</u>
Cu + Ni²⁺ ⟶ Ni + Cu²⁺; -0.599
This is the non-spontaneous direction.
Ni²⁺ is reduced to Ni in the electrolytic cell.
Answer:
158.35 K
Explanation:
Using the general gas law
P₁V₁/T₁ = P₂V₂/T₂ where P₁ = 150.4 kPa, V₁ = 12.2 L, T₁ = 22.7 °C = 273 + 22.7 = 295.7 K, P₂ = 101.3 kPa, V₂ = 9.7 L and T₂ = unknown.
Making T₂ subject of the formula, we have
T₂ = P₂V₂T₁/P₁V₁
Substituting the values of the variables into the equation, we have
T₂ = P₂V₂T₁/P₁V₁
T₂ = 101.3 kPa × 9.7 L × 295.7 K/150.4 kPa × 12.2 L
T₂ = 290,557.777 K/1,834.88
T₂ = 158.35 K