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(a) An ideal gas occupies a volume of 2.0 cm3 at 20°C and atmospheric pressure.

ID: 1401915 • Letter: #

Question

(a) An ideal gas occupies a volume of 2.0 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container. (b) If the pressure of the 2.0-cm3 volume is reduced to 1.6 × 1011 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container? (a) An ideal gas occupies a volume of 2.0 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container. (b) If the pressure of the 2.0-cm3 volume is reduced to 1.6 × 1011 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container? (a) An ideal gas occupies a volume of 2.0 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container. (b) If the pressure of the 2.0-cm3 volume is reduced to 1.6 × 1011 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container?

Explanation / Answer

(a) Volume V = 2.0 cm3 = 2.0 x 10-6 m3

Temperature T = 20 +273 = 293 K

Pressure P = 1atm = 1.01 x 105 Pa

PV = nRT

(1.01 x 105)(2.0 x 10-6) = n (8.314)(293)

n = 8.29 x 10-5 moles

(b) Volume V = 2.0 x 10-6 m3

Pressure P = 1.6 x 10-11 Pa

Temperature T = 293 K

PV = nRT

(1.6 x 10-11)(2.0 x 10-6) = n(8.314)(293)

n = 1.31 x 10-20 moles