Final answer:
To determine the pressure ranking of gases in the flasks, calculate the moles of each gas, given the mass and molar mass. Using the ideal gas law, and knowing the number of moles is directly proportional to pressure, we find Flask B with H₂ has the highest pressure, followed by Flask C with He, and Flask A with CH₄ last.
Step-by-step explanation:
The question asks us to rank three 8-Liter flasks containing different gases in terms of pressure at a constant temperature of 294 K. Each flask contains 5 grams of a different gas: CH₄ in Flask A, H₂ in Flask B, and He in Flask C. We can use the ideal gas law (PV = nRT) to determine the pressures, assuming the gases behave ideally.
To compare pressures, we need to calculate the number of moles (n) of each gas, as the volume (V) and the temperature (T) are constant for all flasks. The number of moles (n) is given by the mass of the gas divided by its molar mass.
- For CH₄ (molar mass = 16.04 g/mol), n = 5g / 16.04 g/mol = 0.311 mol
- For H₂ (molar mass = 2.016 g/mol), n = 5g / 2.016 g/mol = 2.48 mol
- For He (molar mass = 4.00 g/mol), n = 5g / 4.00 g/mol = 1.25 mol
Now, since the pressure (P) is directly proportional to the number of moles (n) when the volume (V) and the temperature (T) are constant, the flask with the highest number of moles will have the highest pressure.
So, the ranking in terms of pressure from highest to lowest is Flask B (H₂) > Flask C (He) > Flask A (CH₄).
The correct answer is D)B > A > C.