Answer:
Nickel is extracted from nickel oxide by reduction with carbon. Nickel is a metal which react with atmospheric oxygen which is very reactive in order to protect the inner surface of metal. Carbon extract oxygen which is attached to the nickel in the form of nickel oxide because carbon is more reactive so it made a chemical bonds with oxygen and nickel oxide is converted into a pure nickel.
Answer:- As per the question is asked, 35.0 moles of acetylene gives 70 moles of carbon dioxide but if we solve the problem using the limiting reactant which is oxygen then 67.2 moles of carbon dioxide will form.
Solution:- The balanced equation for the combustion of acetylene is:

From the balanced equation, two moles of acetylene gives four moles of carbon dioxide. Using dimensional analysis we could show the calculations for the formation of carbon dioxide by the combustion of 35.0 moles of acetylene.

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The next part is, how we choose 35.0 moles of acetylene and not 84.0 moles of oxygen.
From balanced equation, there is 2:5 mol ratio between acetylene and oxygen. Let's calculate the moles of oxygen required to react completely with 35.0 moles of acetylene.

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Calculations shows that 87.5 moles of oxygen are required to react completely with 35.0 moles of acetylene. Since only 84.0 moles of oxygen are available, the limiting reactant is oxygen, so 35.0 moles of acetylene will not react completely as it is excess reactant.
So, the theoretical yield should be calculated using 84.0 moles of oxygen as:

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Answer:The standard reduction potential, Eo , for Pb2+(aq) is greater than that for Mg2+(aq).
Explanation:
Metals are usually arranged in an order of reactivity called activity series. Metals that are high up in the series are good reducing agents with very low (very negative) reduction potentials. Metals with greater (less negative) reduction potentials are found lower in the series. In the image attached, elements were arranged according to their reducing ability. Magnesium is very electro positive hence it is a better reducing agent with a lesser standard reduction potential than lead(refer to the image for numerical values of standard reduction potentials). Hence it displaces lead from solution and the elemental lead deposits on the wire.
The molecule that could diffuse across the plasma membrane is methane (CH4).
<h3>What is diffusion?</h3>
Diffusion is the movement of fluids or substances from regions of high concentration toward regions of lower concentration.
The plasma membrane is the semipermeable membrane that surrounds the cytoplasm of a cell. The semipermeability means that it allows some molecules through but blocks other substances.
The semipermeable plasma membrane readily allows the passage of small hydrophobic and polar molecules.
Therefore, the molecule that could diffuse across the plasma membrane is methane (CH4).
Learn more about semipermeability at: brainly.com/question/1652796
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