If the gas is at 25 ∘c and 1.0 atm, what mass of helium is in the blimp?

Assuming ideal gas, we can use the equation:

PV = nRT

n = PV / RT = (1.0 atm) × (1.65 × 10^5 ft^3 × 28.32 L/ft^3) / ((0.08205 L atm / K mol) × (25 + 273) K)

n = 191013.382 mol He 

(191013.382 mol He) x (4.00g He/mol) = 764053.53 g = 764 kg He

Hope this helps.

Ithink this is what you meant. the temperature at which a liquid begins to boil is called the boiling point. the boiling point of water is 212°f or 100°c.  and at that point will start to turn into steam (gas)