Kaplan FL #1 - Boyle's Law (SOLVED!)

[Formation]

Can someone explain this question to me? I can't follow their explanation at all. :/

ANSWER:

In order to maintain neutral buoyancy, you just want to keep the volume the same. So the volume was 1.6 L at sea level but now is under a gauge pressure of 1 atm, so the volume will half (since the pressure has doubled). So you need to compensate by adding the lost volume. You went from 1.6 L at sea level to 0.8 L at 1 atm gauge pressure so now need to add another 0.8 L to compensate.

So what does 0.8 L mean when you're down 1 atm? Well, the key thing to remember here is that 1 mole of gas is 22.4 L at STP. So if I asked you to add 0.8 L of gas at STP, you would be adding 0.8/22.4 moles. But now, you're under 1 atm gauge pressure. So now remember the ideal gas law. If you double pressure while keeping volume (0.8 L) and temperature (assumed) constant, you must double n as well. So instead of adding 0.8/22.4 moles, you would need 1.6/22.4 moles.

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[747063]

Is that the whole question? I don't follow their explanation either


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[betterfuture]

Yes, please. I had the same confusion on what in the world this question was asking.

 

[Formation]

Is that the whole question? I don't follow their explanation either


Sent from my iPhone using SDN mobile app

Yep, that's the whole question! And as a side note, only information used from the passage was the fact that neoprene is 40% air.

 

[aldol16]

In order to maintain neutral buoyancy, you just want to keep the volume the same. So the volume was 1.6 L at sea level but now is under a gauge pressure of 1 atm, so the volume will half (since the pressure has doubled). So you need to compensate by adding the lost volume. You went from 1.6 L at sea level to 0.8 L at 1 atm gauge pressure so now need to add another 0.8 L to compensate.

So what does 0.8 L mean when you're down 1 atm? Well, the key thing to remember here is that 1 mole of gas is 22.4 L at STP. So if I asked you to add 0.8 L of gas at STP, you would be adding 0.8/22.4 moles. But now, you're under 1 atm gauge pressure. So now remember the ideal gas law. If you double pressure while keeping volume (0.8 L) and temperature (assumed) constant, you must double n as well. So instead of adding 0.8/22.4 moles, you would need 1.6/22.4 moles.

 

[Formation]

In order to maintain neutral buoyancy, you just want to keep the volume the same. So the volume was 1.6 L at sea level but now is under a gauge pressure of 1 atm, so the volume will half (since the pressure has doubled). So you need to compensate by adding the lost volume. You went from 1.6 L at sea level to 0.8 L at 1 atm gauge pressure so now need to add another 0.8 L to compensate.

So what does 0.8 L mean when you're down 1 atm? Well, the key thing to remember here is that 1 mole of gas is 22.4 L at STP. So if I asked you to add 0.8 L of gas at STP, you would be adding 0.8/22.4 moles. But now, you're under 1 atm gauge pressure. So now remember the ideal gas law. If you double pressure while keeping volume (0.8 L) and temperature (assumed) constant, you must double n as well. So instead of adding 0.8/22.4 moles, you would need 1.6/22.4 moles.

Very well explained, thank you!!