Question

Use the ideal gas law to calculate the density of each of the following ideal gases at STP in g/L. Use the Ideal gas constant 0.08205 L*atm/K*mol. (Put your answer in 3 significant figures)

a. carbon dioxide
b. carbon tetrachloride, CCl₄

c. methane, CH₄

Answer 1

a)

P = 1.0atm

T = 273 K

Molar mass of CO2 = 1*MM(C) + 2*MM(O)

= 1*12.01 + 2*16.0

= 44.01 g/mol

Lets derive the equation to be used

we have below equation to be used:

p*V=n*R*T

p*V=(mass/molar mass)*R*T

p*molar mass=(mass/V)*R*T

p*molar mass=density*R*T

Put Values:

1.0 atm *44.01 g/mol = density * 0.08205 atm.L/mol.K *273.0 K

density = 1.9648 g/L

Answer: 1.96 g/L

b)

P = 1.0atm

T = 273 K

Molar mass of CCl4 = 1*MM(C) + 4*MM(Cl)

= 1*12.01 + 4*35.45

= 153.81 g/mol

p*molar mass=density*R*T

Put Values:

1.0 atm *153.81 g/mol = density * 0.08205 atm.L/mol.K *273.0 K

density = 6.8666 g/L

Answer: 6.87 g/L

c)

P = 1.0atm

T = 273 K

Molar mass of CH4 = 1*MM(C) + 4*MM(H)

= 1*12.01 + 4*1.008

= 16.042 g/mol

p*molar mass=density*R*T

Put Values:

1.0 atm *16.042 g/mol = density * 0.08205 atm.L/mol.K *273.0 K

density = 0.7162 g/L

Answer: 0.716 g/L