##### (a) An ideal gas occupies a volume of 1.8 cm3 at 20°C and atmospheric pressure.

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(a) An ideal gas occupies a volume of 1.8 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container.

molecules

(b) If the pressure of the 1.8-cm3 volume is reduced to 2.4 ✕ 10−11 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container?

Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. mol
Jun 21st, 2015

(a) An ideal gas occupies a volume of 1.8 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container.

ans =4.5x10^19 molecules

(b) If the pressure of the 1.8-cm3 volume is reduced to 2.4 ✕ 10−11 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container?

ans = 1. 067 x10 ^4 moles

Jun 21st, 2015

Jun 21st, 2015
screen_shot_2015_06_21_at_2.57.29_am.png

hello, here is the working,

n = PV/RT

P = 1.00 atm
V = 1.8 cm³ = 1.8 cm³ x (1 mL / 1 cm³) x (1 L / 1000 mL) = 0.0018 L
R = 0.0821 Latm/moleK
T = 20C = 20+273.15 = 293.15K

n = (1.00 atm) x (0.0018 L) / [ (0.0821 Latm/moleK) x (293.15K) ]
n = 7.48x10^-5 moles..

finally...
7.48x10^-5 moles x (6.022x10^23 molecules / 1 mole) = 4.50x10^19 molecules.

Jun 21st, 2015

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Jun 21st, 2015
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Jun 21st, 2015
Oct 19th, 2017
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