Question

Calculate the number of moles of air is in the inflated balloon at room temperature as shown in the figure.

The radius of the balloon is 10 cm, and the pressure inside the balloon is 180 kPa.

Answer 1

P = 180 kPa = 180 × 10³Pa

V = `4/3 π"r"^3`

r = 10 cm

R = 8.314 J mol⁻¹k⁻¹

T = 27°C = 300 K

From ideal gas equation of state

PV = μRT

μ = `"PV"/"RT"`

= `(180 xx 10^3 xx 4/3 xx 3.14 xx (10 xx 10^-2)^3)/(8.314 xx 300)`

= `(0.7536 xx 10^3)/2494.2`

= 3.021 × 10⁻⁴ × 10³

μ ≅ 0.3 mol