Chemistry Hw help ideal gas

Question

Calculate the temperature of H2O vapor at a pressure of 340KPa if it has a density of 2.3g/L.

Calculate the molar mass of a gas having a mass of 5.67g at a pressure of 45mmHg, volume of 29L and temperature of 56oC.

Answer 1

2.3 g/L x 1 mol H2O/18 g = 0.128 moles H2O = n

PV = nRT

T = PV/nR = (340 kPa)(1 L) / (0.128 mol)(8.314 kPa*L/K*mol)

T = 319K = 46ºC

PV = nRT

P = 45 mm Hg x 1 atm/760 mm Hg = 0.0592 atm

V = 29 L

n = ?

R = 0.0821 Latm/Kmol

T = 56 + 273 = 329K

Solving for n...

n = PV/RT = (0.0592)(29) / (0.0821)(329)

n = 0.0636 moles

molar mass = g/mol = 5.67 g / 0.0636 moles

molar mass = 89.2 g/mol