An evacuated glass vessel weighs 50 g when empty, 144.0 g when filled with a liquid of density 0.47 g ml-1 and 50.5 g when filled with an ideal gas at 760 mm Hg at 300 K. The molar mass of the ideal gas is: (R= 0.0821 L atm. K-1 mol-1)

Question

An evacuated glass vessel weighs 50 g when empty, 144.0 g when filled with a liquid of density 0.47 g ml-1 and 50.5 g when filled with an ideal gas at 760 mm Hg at 300 K. The molar mass of the ideal gas is: (R= 0.0821 L atm. K-1 mol-1) (A) 61.575 (B) 130.98 (C) 123.75 (D) 47.87

Tardigrade Admin · Accepted Answer

Weight of empty glass vessel = 50 g Weight of glass vessel filled with liquid = 144.0 g ∴ Weight of liquid =144-50=94 g Density of liquid =0.47 gmL -1 ∴ Volume of liquid =(94/0.47)=200 mL =0.2 L Mass of glass vessel filled with gas =50.5 g ∴ Mass of gas (m)=50.5-50=0.5 g By using ideal gas equation, pV =( m / W ) RT where, p =760 mm, Hg =1 atm, V= 0.2 L T =300 K and R =0.0821 L atm K -1 mol -1 ∴ Molar mass ( M )=( mRT / pV ) =(0.5 × 0.0821 × 300/1 × 0.2) =61.575 g mol -1

Q. An evacuated glass vessel weighs $50 g$ when empty, $144.0 g$ when filled with a liquid of density $0.47 g m l^{- 1}$ and $50.5 g$ when filled with an ideal gas at $760 mm H g$ at $300 K$ . The molar mass of the ideal gas is: ( $R = 0.0821 L$ atm. $K^{- 1} m o l^{- 1}$ )

$61.575$

$130.98$

$123.75$

$47.87$

$87.943$

Q. An evacuated glass vessel weighs 50g when empty, 144.0g when filled with a liquid of density 0.47gml−1 and 50.5g when filled with an ideal gas at 760mmHg at 300K. The molar mass of the ideal gas is: (R=0.0821L atm. K−1mol−1)

61.575

130.98

123.75

47.87