Chemistry Lab using Hcl and Sodium Bicarbonate to recreate a airbag

Question

I have a 1.12L ziplock bag. I have to combine the proper amount of HCl and NaHCO3 in the bag for a lab to fill the bag enough so that it is plump but will not pop. The temperature of the room will be 298K at 0.96 Atm. I need to find how much of each substance in Liters to combine in the bag so that it will simulate an air bag. The molarity of the Hcl solution is 3 moles for each liter of solution. The molarity of the sodium bicarbonate is 1M. The chemical equation is HCl + NaHCO3 > H20 + CO2 + NaCl. Please answer.

Answer 1

If the volume of the bag is 1.12 L, and you want it plump, but not to break, then let's say you want to fill it with 1 L of gas (~89% full). To do this, we will want to generate 1 L of gas (CO2) from the reaction between HCl and NaHCO₃. The reaction looks like this:

HCl + NaHCO₃ ==> NaCl + H₂CO₃ ==> H₂O + CO₂(g)

We use the ideal gas law to find how many moles of CO₂ we need:

PV = nRT

P = pressure = 0.96 atm

V = volume = 1 L

n = moles of CO₂ = ?

R = gas constant = 0.0821 Latm/Kmol

T = temperature in Kelvin = 298K

Solving for n we have..

n = PV/RT = (0.96)(1) / (0.0821)(298(

n = 0.039 moles CO₂ needed

To get 0.039 mols CO₂ we need 0.039 mols NaHCO₃ and at least 0.039 mols HCl so that it isn't limiting.

0.039 mols NaHCO₃ x 1 L / 1 mol = 0.039 L = 39 mls of NaHCO₃

0.039 mols HCl x 1 L / 3 mol = 0.013 L = 13 mls HCl (minimum)

So, to be sure you have excess HCl, you might consider using 20 or more mls of 3 M HCl