November 29, 2021, 04:46:57 AM
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### Topic: Calculate the depth to which a balloon full of Kr must be pushed to make it sink  (Read 287 times)

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#### moreche28

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##### Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« on: October 23, 2021, 10:29:23 AM »
Hello.

I've been struggling to solve the following problem. We have to calculate the depth (in m) to which a balloon full of Kr must be pushed underwater to make it sink to the bottom of the sea. It takes place at 25 degrees Celsius, we know that p (atm) = 101 325 Pa, density (of sea H2O) = 1.04 g/cm3, g = 9.81 m/s2 and the M (Kr) = 83,8 g/mol, and that Kr acts as an ideal gas.

Firstly, I've calculated the density of Kr ( = 3.74 g/dm3), and I know that the p (fluid) = ρ * h * g. Does anyone have any ideas about what to do next?

Thank you!

#### Orcio_Dojek

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##### Re: Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« Reply #1 on: October 23, 2021, 12:18:38 PM »
Density of the Kr must be higher that density of the sea water. The higher pressure the higher density of the gas.

#### moreche28

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##### Re: Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« Reply #2 on: October 23, 2021, 12:39:53 PM »
Thank you. Hopefully, I've managed to solve it using the following equation: p1*V1 = p2*V2, and therefore: p1*V1 = ρ * h * g * (m/ρ) => p1*V1 = h * g * m. But how should I calculate the new density?

#### Orcio_Dojek

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##### Re: Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« Reply #3 on: October 23, 2021, 12:50:37 PM »
Density of the Kr must be higher that density of the sea water (1,04 g/ml).

#### moreche28

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##### Re: Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« Reply #4 on: October 23, 2021, 12:59:04 PM »
Yes, I've got this. But I'm not sure the equation is right.

#### Orcio_Dojek

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##### Re: Calculate the depth to which a balloon full of Kr must be pushed to make it sink
« Reply #5 on: October 23, 2021, 01:24:32 PM »
Density is the mass to the volume ratio (higher pressure decreases the volume).