Hi, your answer is correct.
Answer:

Explanation:
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In this case, according to the Dalton's law, which explains that the total pressure of a gaseous system equals the sum of the partial pressures of the gases composing, for the gaseous mixture composed by oxygen, nitrogen and carbon dioxide it would be possible to write:

Now, given the pressure of the system and those of oxygen and nitrogen, we calculate that of carbon dioxide as shown below:

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Answer is: silicon isotope with mass number 28 has highest relative abundance, this isotope is the most common of these three isotopes.
Ar₁(Si) = 28; the average atomic mass of isotope ²⁸Si.
Ar₂(Si) =29; the average atomic mass of isotope ²⁹Si.
Ar₃(Si) =30; the average atomic mass of isotope ³⁰Si.
Silicon (Si) is composed of three stable isotopes, ₂₈Si (92.23%), ₂₉Si (4.67%) and ₃₀Si (3.10%).
ω₁(Si) = 92.23%; mass percentage of isotope ²⁸Si.
ω₂(Si) = 4.67%; mass percentage of isotope ²⁹Si.
ω₃(Si) = 3.10%; mass percentage of isotope ³⁰Si.
Ar(Si) = 28.086 amu; average atomic mass of silicon.
Ar(Si) = Ar₁(Si) · ω₁(B) + Ar₂(Si) · ω₂(Si) + Ar₃(Si) · ω₃(Si).
28,086 = 28 · 0.9223 + 29 · 0.0467 + 30 · 0.031.
Answer:
B.
Explanation:
Everything else is not a drawback, it is a benefit.