1) Write the balanced chemical equation:
2Al + 6HCl ---> 2AlCl3 + 3H2
2) Calculate the molar masses of Al and HCl and use them to convert the data to moles
Al: 27g/mol => 10.7 gAl / 27g/mol = 0.396 mol Al
HCl: 1g/mol + 35.5 g/mol = 36.5g/mol => 42.5gHCl / 36.5g/mol = 1.164 mol HCl
Theoretical ratio: 6 mol HCl / 2 mol Al = 3:1
Actual ratio: 1.164 mol HCl / 0.396 mol Al = 2.94 : 1
Then there is a little bit less HCl than the predicted by theoretical ratio, which means that this is the limitant reagent.
3) Use the amount of HCl to make the calculations of the proucts obtained.
Theoretical ratio: 3 mol H2 / 6 mol HCl = 1:3
1.164 mol HCl 1 mol H2 / 3 mol HCl = 0.388 mol H2
4) Use the ideal gas formula to obtain the volume
pV = n RT
p = 725 mmHg 1atm / 760mmHg = 0.954 atm
n = 0.388 mol
R = 0.082 atmliter /Kmol
T = 47 °C + 273.15 = 320.15K
V = nRT/p = 0.388 mol 0.082 [atmliter/Kmol] 320.15K / 0.954 atm = 10.7 liter
Answer: 10.7 liter
