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Question 1
Acetone (CH3)2CO is a volatile Liquid that can be readily converted to vapour.
Calculate the density of acetone vapour at 100,000 Pa and 398 K in kg/m3. Assume
ideal behaviour and use R=8.314 J/mol.K.
Your Answer:
Answer

Respuesta :

Edufirst

Answer:

  • 1.76 kg/m³

Explanation:

1) Data:

a) Chemical formula: (CH₃)₂CO

b) P = 100,000 Pa

c) T = 398 K

d) D = ?

e) R = 8.314 J / mol.K

2) Principles and formulae:

a) Ideal behaviour of a gas means that it follows the ideal gas equation:

  • PV = nRT

b) Density, D = mass / volume

c) mass in grams = n × molar mass

3) Solution:

a) Transform the ideal gas equation to solve for the density:

  • PV = nRT                      ( n = mass in grass / molar mass)

  • PV = (mass in grams / molar mass) RT

  • (mass in grams / V) = P × molar mass / (RT)

  • mass in kg × 1,000 (g/ kg) / V = P × molar mass / (RT)

  • (mass in kg / V) =  P × molar mass / (1,000RT)

  • D = P × molar mass / (1,000RT)

b) Molar mass of (CH₃)₂CO: 58.08 g/mol

c) Substitute and compute:

  • D = 100,000 Pa × 58.08 kg/mol / ( 1,000 × 8.314 J/mol.K × 398 K)

* (note that by dividing by 1,000 the molar mass is transformed from g/mol to kg/mol)

  • D = 1.76 kg/m³← answer

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