December 06, 2022, 03:00:01 AM
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### Topic: Some help please? This problem is driving me crazy...  (Read 179 times)

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#### Shabazz

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##### Some help please? This problem is driving me crazy...
« on: November 23, 2022, 09:37:49 PM »
Hello All,

The danger point in breathing sulfur dioxide for humans is 2620 μg/m3. How many ppm is this value? Final Answer: 0.00183 ppm or 1.83 ppb.

I feel that the answer provided is incorrect. I've tried every approach and angle to solve this question. Can someone on this forum provide some guidance? I can't seem to get the answer provided. Keen to know what I'm doing wrong?

My understanding is that ppm is = moles of substance/ moles of the mixture.

However, when I calculate the moles of SO2 and find the moles of Air in 1m^3 Air (Basis), I find the ratio of the two and get nowhere near that value given in the solutions.

#### Borek

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##### Re: Some help please? This problem is driving me crazy...
« Reply #1 on: November 24, 2022, 03:18:09 AM »
Looks like an error to me.

Most common meaning of ppm/ppb is mass over mass. This doesn't produce 183 ppb either.

Feels like whoever calculated the answer might have by mistake used density not of the air, but of pure oxygen? That produces very similar result.
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