Both jacques charles and joseph louis guy-lussac were avid balloonists. in his original flight in 1783, jacques charles used a balloon that contained approximately 31100 l of h2. he generated the h2 using the reaction between iron and hydrochloric acid: fe(s)+2hcl(aq)→fecl2(aq)+h2(g)
how many kilograms of iron were needed to produce this volume of h2 if the temperature was 21 ∘c? (for simplicity, assume that the pressure experienced by the balloon will be 1.00 atm.)

Explanation:

First of all, we need  to calculate the moles of H2. Assuming the H2 is an ideal gas:

Now, to produce 1 mol of H2 is required 1 mol of Fe:

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2