# Chem

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Hello!

A 22.0 L cylinder containing helium gas at a pressure of 28.1 atm is used to fill a weather balloon in order to lift equipment into the stratosphere. What is the final pressure (in atm) in the cylinder after a 101 L balloon is filled to a pressure of 1.23 atm.

I found the pressure of the gas in the balloon, if it were all in the small cylinder then used Dalton's law of partial pressure to get the final pressure in the small cylinder and got 6.036. This is not right, so can someone help?

Calculate vrms, the root mean square velocity, in m/s of SO2 molecules at 210 oC.

I used the formula, but got a weird answer:5.044x10^11. Help?

Use the van der Waals equation to calculate the pressure, in atm, of 44.75 mol of hydrogen at 64 oC in a 2.15 L container.

This is also an equation problem, but I can't get it. I got the answer to be 575.575.

• Chem - ,

For the cylinder/balloon problem I would do this.
PV = nRT and calculate mols gas in the cylinder. You have no T listed so use a convenient one and keep it consistent.

Use PV = nRT and solve for mols in the balloon.
Subrtact, initial mols cylinder-mols balloon = mols still in the cylinder.
Then PV = nRT and solve for pressure in the cylinder. I get something like 22 atm (not an exact answer).