Answer:The purple color is due to a mixture of the pink aqua complex and blue chloro complex and is not due to a new species.
Explanation:
The pink aqua complex of cobalt can be in equilibrium with blue chloro complex of cobalt giving rise to a purple colour. This equilibrium is governed by Le Chaterliers principle. A change in chloride or water concentration could shift the equilibrium towards any of the species causing its colour to become the dominant colour of the solution.
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:
D) 0.50 mole of Ne
Explanation:
Given data:
Number of molecules of nitrogen = 3.0×10²³ molecules
Which sample contain same number of molecules as nitrogen= ?
Solution:
A) 0.25 mole of O₂
1 mole = 6.022×10²³ molecules
0.25 mol × 6.022×10²³ molecules / 1 mol
1.51×10²³ molecules
B) 2.0 moles of He.
1 mole = 6.022×10²³ molecules
2.0 mol × 6.022×10²³ molecules / 1 mol
12.044×10²³ molecules
C) 1.0 moles of H₂
1 mole = 6.022×10²³ molecules
D) 0.50 mole of Ne
1 mole = 6.022×10²³ molecules
0.50 mol × 6.022×10²³ molecules / 1 mol
3.0×10²³ molecules
Answer: The answer is blue, white, yellow-white, orange.
Explanation: These are the two basic reasons for different star colors:
Temperature – cooler stars are red, warmer ones are orange through yellow and white. The hottest stars shine with blue light
Age – As a star ages it produces different chemicals which burn at different temperatures. We can use a star’s color to show its relative age
