13. What is the volume of air required to completely burn 1 L of CO? Assume that all volumes are measured at the same temperature and pressure and
also that air contains one-fifth by volume of oxygen

Approximately .

Explanation:

Start by finding the balanced equation for the reaction between and .

When is in excess, reacts with to produce .

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Assume that the coefficient of is . ( is the only product of this reaction.)

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Apply the conservation of atoms to find the coefficient of the other two species.

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Multiply all coefficients in this equation by to eliminate the fraction.

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Note the ratio between the coefficient of and in this balanced equation:

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Assume that both and behave like ideal gases. Under the same temperature and pressure, the ratio between the volume of these two gases will match the ratio between the quantity of their particles:

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In other words, in this reaction, every one unit volume of will react with two unit volume of .

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Under these assumptions:

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The question stated that when measured by volume, one-fifth of the air is oxygen. That is:

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Rearrange to obtain:

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Therefore: