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 : The correct option is (C) : Dew forms on grass when water vapor forms when molecules cool and join together.
Explanation :
Air contains a small amount of water vapors. When the temperature of an object is lowered than the ambient temperature, the vapors get condensed and small water droplets are formed on the object.
During night time, when the temperature is lowered, the blades of grass become cool. As a result, the vapor molecules slow down and eventually come close to each other. They join together to form liquid water which gets deposited on the blades in the form of dew drops.
The only option that explains this process is option C.
Answer : The correct option is, transverse wave.
Explanation :
Longitudinal waves : It is defined as the waves in which the particles of the medium move in the direction of the wave.
Transverse wave : It is defined as the waves in which the particles of the medium travel perpendicularly to the direction of the wave.
Surface wave : It is defined as a combination of transverse and longitudinal waves.
From the given image we conclude that, this illustration depict the transverse wave because the particles of the medium move perpendicularly to the direction of the wave.
Hence, the type of wave is, transverse wave
88226Ra→ 86222Rn + 24He is the reaction that describes an alpha emission because radiations are released.
<h3>Describes an alpha emission?</h3>
Alpha radiation occurs when the nucleus of an atom becomes unstable and alpha particles are released in order to restore stability. Alpha decay occurs in elements that have high atomic numbers, such as uranium, radium, and thorium etc.
So we can conclude that 88226Ra→ 86222Rn + 24He is the reaction that describes an alpha emission because radiations are released.
Learn more about radiation here: brainly.com/question/893656
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Answer:
Thermoplastics have low melting temperature because of the week van der Waals bonds between their Long Chain Molecules
Polymer chains once synthesized they will remain stable in the environment because of the strong covalent bonds in the Long Chain Molecules
Explanation:
Thermoplastics are polymers that are easily melted and changed to another shape as many times as possible. They become molten when they are heated and solidify when cooled. Examples of thermoplastics include; polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamides, polyesters, and polyurethanes.
Polymers are organic materials that consists of a long chain of atoms held together by strong covalent bonds. Polymers constitute an important environmental concern because most polymers are non biodegradable and remain in the environment almost indefinitely.
