Question

if a 1.85g mass of zinc produces 475 mL og gas and your balloon weighs 0.574 g and the room temperature is 20.5°C. calculate the amount of zinc needed to produce enough gas to get your balloon airborne by adding 1 mL to the required balloon volume so that its density is less than that of the surrounding air.

Answer 1

You will use an ideal gas equation here. Let us denote 'x' as the unknown sample of zinc if another 1 ml of it is added to make a total of 476mL gas. The ideal gas equation is PV = nRT. Assume atmospheric conditions and then substitute everything to the equation.

(1atm)(0.476L) = (1.85 + x)(0.08206 L-atm/mol-K)(20.5+273K)
x = 1.83 g of zinc