Physical Chemisttry Pressure

[jkn1121]

A man used a hydrogen-filled balloon to fly from Paris 25km into the French side. What’s the mass density of hydrogen relative to air at the same temperature/pressure? What mass of payload can be lifted by 10kg of hydrogen, neglect the mass of the balloon?

 

 

[swansont]

What work have you done on the problem?

[Mr Skeptic]

Also you'll need extra data (find it online) to compare to air density.

 

What will be the volume of your hydrogen at, say, standard temperature and pressure?

[jkn1121]

Standard Stage:

 

Vol= 24.8 dm^3

Pressure: 1 atm

 

I'm not sure where to start or formula to use, not sure if the formula PV=nRT?

[swansont]

Standard Stage:

 

Vol= 24.8 dm^3

Pressure: 1 atm

 

I'm not sure where to start or formula to use, not sure if the formula PV=nRT?

 

PV=nRT is a good place to start

[Mr Skeptic]

I'm not sure where to start or formula to use, not sure if the formula PV=nRT?

 

Yes, that is a very useful formula. n you can calculate for a given mass of sample, R is a constant. So long as you're dealing with ideal gases (which should be the case here), then the effects of P and T will be the same for both gas samples, so that they will cancel out.

[jkn1121]

If P and T cancels out, so R is given and V is 24.8 dm^3, I calculate for n

 

 

PV= nRT

V= nR

n= V/R

n= 24.8/.0826 = 302.21mol * 4g/mol = 1208g

 

 

 

[swansont]

4g/mol?

[jkn1121]

oh crap i take He g/mol instead of H2, so the answer is 302.21g