3 of them left and i just need points lol sorrrry
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:
54
Explanation:
Given symbol of the element:
I⁻
Number of electrons found in an ion with the symbol:
This is a iodine ion:
For an atom of iodine:
Electrons = 53
Protons = 53
Neutrons = 74
An ion of iodine is one that has lost or gained electrons.
For this one, we have a negatively charged ion which implies that the number of electrons is 1 more than that of the protons.
So, number of electrons = 53 + 1 = 54
The number of electrons in this ion is 54
Answer: 5.18
Explanation:
Mathematically, pOH is expressed as
pH = -log(OH-)
where OH-is the concentration of hydroxide ion
So, pOH calculations are as follows
pOH = -log(1.50x10-9 M)
pOH = -(-8.82)
pOH = 8.82 [the two minus signs cancelled out]
Since pOH = 8.82; apply the formula
pH + pOH = 14 to get pH of the solution
Hence, pH + pOH = 14
pH + 8.82 = 14
pH = 14 - 8.82
pH = 5.18
Thus, the pH of a solution with a 1.50x10-9 M hydroxide ion concentration is 5.18 (slightly acidic)
Answer:
D. 18.7 grams
Explanation:
The coefficients are the key.
Create a proportion with them, and the molar mass, and then solve for x:
= 0.6944 mmol Ca(OH)₂