A flask contains 9.15 moles of nitrogen and 5.14 moles of helium. What is the partial pressure of the helium gas if the total pressure is 3.29.

To solve this problem, we need to use Dalton's Law of Partial Pressures. This law states that the total pressure exerted by a mixture of gases is equal to the sum of the pressures that each gas would exert if it were alone.

Step 1: Calculate the total moles of gas in the flask.

Total moles = moles of nitrogen + moles of helium Total moles = 9.15 moles + 5.14 moles = 14.29 moles

Step 2: Calculate the mole fraction of helium.

Mole fraction of helium = moles of helium / total moles Mole fraction of helium = 5.14 moles / 14.29 moles = 0.3597

Step 3: Calculate the partial pressure of helium.

Partial pressure of helium = mole fraction of helium * total pressure Partial pressure of helium = 0.3597 * 3.29 atm = 1.18 atm

So, the partial pressure of the helium gas is 1.18 atm.