A furnace has a stack

$100$

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$100$ft high. The gases in the stack have

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$=$

$28$

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$/$

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M$=28$g$/$mol and

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$=$

$30$

$0$

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T$=300$

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F$.$ If the

pressures of the air and the gas in the stack are equal at the top of the stack, what is the pressure difference at the

bottom of the stack?