At 18 degree Celsius and 765mmHg,1.30 liters of gas has mass 2.80g compute the molecular mass of the gas?

1 Answer
Apr 10, 2018

#"50.9 g/mol"#

Explanation:

Use ideal gas equation,

#"PV = nRT"#

Where,

  • #"P = Pressure = 765 mmHg" = "765 mmHg"/"760 mmHg/atm" = "1.01 atm"#
  • #"V = Volume = 1.30 L"#
  • #"R = Gas constant = 0.0821 L atm / (mol K)"#
  • #"T = Temperature (in Kelvin) = 18°C + 273 = 291 K"#
  • #"n" = ?#

#"n" = "PV"/"RT" = "1.01 atm × 1.30 L"/"0.0821 L atm / (mol K) × 291 K" = "0.0550 mol"#

Molar mass #= "2.80 g"/"0.0550 mol" = "50.9 g/mol"#