Answer to Question #349567 in General Chemistry for Siyabonga

Question

What is the density of CO2 at 25°C and 750 Torr?

[1] 0.472 g/L [2] 1.78 g/L

[3] 1.82 g/L

[4] 2.12 g/L

[5] None of the above 

Answer 1

Given:

M(CO₂) = 44.01 g mol⁻¹

P = 750 torr

T = 25°C + 273.15 = 298.15 K

R = universal gas constant = 62.3636 L torr K⁻¹ mol⁻¹

Solution:

Ideal gas law can be used.

Ideal gas law can be expressed as: PV = nRT

Rewrite the expression taking into account the fact that n = m / M:

MPV = mRT

Rewrite the expression taking into account the fact that d = m / V:

MP = dRT

To find the density, solve the equation for d:

d = MP / RT

d = (44.01 g mol⁻¹ × 750 torr) / (62.3636 L torr K⁻¹ mol⁻¹ × 298.15 K) = 1.775 g L⁻¹ = 1.78 g L⁻¹

d = 1.78 g L⁻¹

Answer: [2] 1.78 g/L