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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Molarity is a measure of a solution's concentration calculation by getting the ratio of the number of moles of solute to the total volume of solution. This has a unit of M or molar, equivalent to mole/L.
It is more important and meaningful to know the molarity rather than if the solution is dilute or concentrated because molarity gives the QUANTITATIVE approach of knowing the concentration while the second one only gives us the QUALITATIVE description of the solution. Hence, we are able to calculate for other unknown parameters if we have the molarity known.
Answer:
Mole fraction of C₄H₄S = 0.55
Explanation:
Mole fraction is moles of solute / Total moles
Total moles are the sum of moles of solute + moles of solvent.
Let's find out the moles of our solute and our solvent.
Mass of solute: 55g
Mass of solvent: 65g
Mol = Mass / molar mass
55 g / 84.06 g/mol = 0.654 moles of C₄H₄S
65 g /123 g/mol = 0.529 moles of C₂H₃BrO
Total moles = 0.654 + 0.529 = 1.183 moles
Mole fraction of thiophene = Moles of tiophene / Total moles
0.654 / 1.183 = 0.55
Yes, anything that lives. Cells have a nucleus, they are alive and can reproduce. (Not man made/abiotic)
In general, the diffusion coefficient is inversely proportional to pressure. This is also an observed fact: gas production rates from coal seams tend to increase as the reservoir pressure goes down.