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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: vhpk on June 17, 2009, 04:51:16 AM

Title: A physical chemistry problem
Post by: vhpk on June 17, 2009, 04:51:16 AM

I have difficulty solving an exercise in Physical Chemistry of Atkins.
A diving bell has an air space of 3.0 m³ when on the deck of a boat. What is the volume of the air space when the bell has been lowered to a depth of 50 m? Take the mean density of sea water to be 1.025 gcm^{- 3} and assume that the temperature is the same as on the surface.
The answer is 0.5m³, however, I don't know how to solve the problem as I don't know what the relationship between the density and the volume when temperature is constant apart from : V =mD, but it can't be praticed in this case.
Thank you for reading and helping me solve this :)

Title: Re: A physical chemistry problem
Post by: Borek on June 17, 2009, 05:43:03 AM

Use density of water to calculate pressure.

Title: Re: A physical chemistry problem
Post by: vhpk on June 17, 2009, 05:58:27 AM

Okay,
P =Dgh = 1.025x10^-6x9.8x50 =5.0225x10^-4, right ?
Then use:
P₁V₁ = P₂V₂
With P₁ = 1.0atm, V₁=3.0m³, P2=5.0225x10^-4 and calculate V2.
Is that right ???

Title: Re: A physical chemistry problem
Post by: Borek on June 17, 2009, 07:07:09 AM

Watch your units.