An evacuated glass vessel weighs 40.0 g when empty, 135.0 g when filled with a liquid of density 0.95 g mL -1 and 40.5 g when filled with an ideal gas at 0.82 atm at 250 K. The molar mass of the gas in g mol -1 is: (Given: R =0.082 L atm K -1 mol -1 )

Question

An evacuated glass vessel weighs 40.0 g when empty, 135.0 g when filled with a liquid of density 0.95 g mL -1 and 40.5 g when filled with an ideal gas at 0.82 atm at 250 K. The molar mass of the gas in g mol -1 is: (Given: R =0.082 L atm K -1 mol -1 ) (A) 35 (B) 50 (C) 75 (D) 125

Tardigrade Admin · Accepted Answer

Mass of liquid =135-40=95 g Volume of liquid =( text mass / text density )=(95/.95) mL =100 mL =0.1 L mass of ideal gas =40.5-40 g =0.5 g PV = nRT 0.82 × 0.1=((0.5/M)) × 0.082 × 250 M=125

Q. An evacuated glass vessel weighs $40.0 g$ when empty, $135.0 g$ when filled with a liquid of density $0.95 g m L^{- 1}$ and $40.5 g$ when filled with an ideal gas at $0.82 a t m$ at $250 K$ . The molar mass of the gas in $g m o l^{- 1}$ is :
(Given : $R = 0.082 L a t m K^{- 1} m o l^{- 1}$ )

35

50

75

125

Mass of liquid $= 135 - 40 = 95 g$
Volume of liquid $= \frac{mass}{density} = \frac{95}{.95} m L$ $= 100 m L = 0.1 L$
mass of ideal gas $= 40.5 - 40 g = 0.5 g$
$P V = n RT$
$0.82 \times 0.1 = (\frac{0.5}{M}) \times 0.082 \times 250$
$M = 125$

Q. An evacuated glass vessel weighs 40.0g when empty, 135.0g when filled with a liquid of density 0.95gmL−1 and 40.5g when filled with an ideal gas at 0.82atm at 250K. The molar mass of the gas in gmol−1 is : (Given : R=0.082LatmK−1mol−1 )

35

50

75

125

Mass of liquid =135−40=95g Volume of liquid = density mass ​=.9595​mL =100mL=0.1L mass of ideal gas =40.5−40g=0.5g PV=nRT 0.82×0.1=(M0.5​)×0.082×250 M=125

Q. An evacuated glass vessel weighs $40.0 g$ when empty, $135.0 g$ when filled with a liquid of density $0.95 g m L^{- 1}$ and $40.5 g$ when filled with an ideal gas at $0.82 a t m$ at $250 K$ . The molar mass of the gas in $g m o l^{- 1}$ is :
(Given : $R = 0.082 L a t m K^{- 1} m o l^{- 1}$ )

Mass of liquid $= 135 - 40 = 95 g$
Volume of liquid $= \frac{mass}{density} = \frac{95}{.95} m L$ $= 100 m L = 0.1 L$
mass of ideal gas $= 40.5 - 40 g = 0.5 g$
$P V = n RT$
$0.82 \times 0.1 = (\frac{0.5}{M}) \times 0.082 \times 250$
$M = 125$