Pick up plastic, reduce waste, reduce pollutants
Size, speed and angle of the falling object determine the size shape and complexity of the resulting crater
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:
11%
Explanation:
1) Calculate van 't Hoff factor:
Δt = i Kf m
0.31 = i (1.86) (0.15)
i = 1.111
2) Calculate value for [H+]:
CCl3COOH ⇌ H+ + CCl3COO¯
total concentration of all ions in solution equals:
(1.11) (0.15) = 0.1665 m
This is a molality, but we will act as if it a molarity since we will assume the density of the solution is 1.00 g/cm3, which makes the molarity equal to the molality.
0.1665 = (0.15 − x) + x + x
x = 0.0165 M
3) Calculate the percent dissociation:
0.0165/ 0.15 = 11 %
Answer: The statement that is not a determining factor in formation of intrusive igneous rocks is 'None of the above' and Magma cools very fast beneath the Earth's surface.
Explanation:
Rocks are naturally occurring solid materials that are made up of different types of minerals which affects it's texture and colours. The three main types of rocks are:
--> sedimentary rocks,
--> metamorphic rocks and
--> igneous rocks.
Igneous rocks are formed from the crystallization and solidification of hot molten rocks which originates from deep within the earth. Depending on where the molten rock solidifies, the igneous rock is divided into two, namely:
--> intrusive igneous rock and
--> extrusive igneous rock.
The INTRUSIVE IGNEOUS rocks are formed within or deep beneath the earth surface when the hot magma SLOWLY cools over millions of years until it solidifies. The slow cooling allows large crystals to grow.
Therefore the statements (None of the above and Magma cools very fast beneath the Earth's surface) are not a determining factor.
