BOb asked in Science & MathematicsPhysics · 3 weeks ago

Physics Homework Help !?

0.17 mol of argon gas is admitted to an evacuated 80 cm3 container at 20 ∘ C. The gas then undergoes an isothermal expansion to a volume of 400 cm3 .

What is the final pressure of the gas?

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  • 3 weeks ago

    assuming that is 80 cm³

    80 cm³ = 80 mL = 0.08 L

    400 cm³ = 400 mL = 0.4 L

    20ºC = 293.16 K

    initial

    P = nRT/V = (0.17)(0.08206)(293.16) / (0.08) = _____ atm

    final

    P₂ = P₁V₁/V₂ = [ (0.17)(0.08206)(293.16) / (0.08) ] [ (0.08/0.4 ]

    P₂ =  (0.17)(0.08206)(293.16) / (0.4) = _____ atm

    but we could have just plugged 0.4 L into the first equation.

    Constant temperature (Boyle's law)

    P₁V₁ = P₂V₂

    P₂ = P₁V₁/V₂

    V₂ = P₁V₁/P₂

    Ideal gas law

    PV = nRT

    n = number of moles

    R = gas constant = 0.08206 (atm∙L)/(mol∙K)

                       8.314 L∙kPa/mol∙K

                       0.08314 L∙bar/mol∙K

                       62.36 L∙torr/mol∙K

                       62.36 L∙mmHg/mol∙K

    T = temperature in kelvins

    P = absolute pressure in atm, kPa, bar, torr

    V = volume in liters

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