Ideal Gas Law Question: Calculating Final Balloon Volume at High Altitude

[blackjack18]

A sealed balloon is filled with 1.00 L of He gas at 23 deg C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 220 torr and the temperature is -31 deg C. What is the final volume of the balloon after it reaches an altitude where the pressure is 220 torr?

If I should use the Ideal Gas Law, Pv= nRT, how do I find the number of moles?

 

[LowlyPion]

A sealed balloon is filled with 1.00 L of He gas at 23 deg C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 220 torr and the temperature is -31 deg C. What is the final volume of the balloon after it reaches an altitude where the pressure is 220 torr?

If I should use the Ideal Gas Law, Pv= nRT, how do I find the number of moles?

You are not asked for the number of moles. (Hint: You don't need it either.)

https://www.physicsforums.com/showpost.php?p=1914382&postcount=14

 

[baba89]

To calculate the final volume of the balloon at high altitude, we will use the Ideal Gas Law equation Pv=nRT, where P is pressure, v is volume, n is the number of moles, R is the gas constant, and T is temperature.

To find the number of moles, we can rearrange the equation to n=PV/RT. We already know the initial volume (1.00 L), pressure (1.00 atm), and temperature (23 deg C or 296 K) of the gas in the balloon. We can also convert the given pressure at high altitude (220 torr) to atm by dividing by 760 torr/atm, giving us 0.289 atm. The temperature at high altitude is given as -31 deg C or 242 K.

So, plugging in these values into the equation n=PV/RT, we get n=(1.00 atm)(1.00 L)/(0.289 atm)(242 K)= 0.146 moles.

Now that we have the number of moles, we can use it to calculate the final volume of the balloon at high altitude. Again, using the Ideal Gas Law equation, we get v=nRT/P=(0.146 moles)(0.289 atm)(242 K)/(220 torr)= 0.044 L or 44 mL.

Therefore, the final volume of the balloon at high altitude where the pressure is 220 torr and the temperature is -31 deg C would be 44 mL. It is important to note that this calculation assumes that the balloon and gas inside it behave ideally, which may not always be the case in real-world scenarios.