A large balloon used to sample the upper atmosphere is filled with 465 m3 of helium. What is the mass of the helium (in kg)?

Answer 1

Hi Samaria,

In order to relate volume and mass, you must use the following relationship with density:

density = mass/Volume

Otherwise written as ρ = m/V (for three dimensional density anyway):

If we multiply the formula by V on both side, it yields:

(ρ_helium)(V_helium) = m_helium

or:

m_helium = (ρ_helium)(V_helium)

Now we just need the density of helium which a quick Google search can provide.

ρ_helium = 0.1786 g/L

Let's convert this measure to relevant units: ρ_helium = 0.1786 g/L (1000 L/ 1 m^3) = 178.6 g/m^3

But we need kg/m^3 units since the question request for kilograms (kg) and provide volume of m^3 units.

ρ_helium = 178.6 g/m^3 (1kg/1000g) = 0.1786 kg/m^3

ρ_helium = 0.1786 kg/m^3

Going back to the formula: m_helium = (ρ_helium)(V_helium), now we can calculate the mass of the helium:

m_helium = (0.1786 kg/m^3)(465 m^3)

m_helium = 83.049 kg

That's one big and heavy balloon!