Once ignited, it will produce 120 cubic feet of #O_2# at 0.5 psi, enough to support 100 persons. After balancing the equation, how do you compute the mass of #NaClO_3# required to generate the moles of gas needed to support the 100 crew members at 300K?

Question

On submarines, chlorate candles are used to produce emergency oxygen. Once ignited, it decomposes via: #NaClO_3(s) -> NaCl(s) + O_2(g)#.

Henry Antrim · Accepted Answer

#NaClO_3(s) rarr NaCl(s) + 3/2O_2(g)uarr#

Typically, this reaction is catalyzed by an oxygen transfer reagent, #MnO_2#. This is a very convenient preparation of laboratory oxygen (and also, as you say, on board a submarine or submersible! This is not a use of which I would like to have experience.)

Your question is rather open-ended, so I will try to address it like this. From this site, we learn that the average punter consumes #11# #m^3# of oxygen gas per day. This is #11xx10^3*L#.

Given that #n=(PV)/(RT)# #=#

#(21%xx1*atmxx11xx10^3*L)/(0.0821*L*atm*K^-1*mol^-1xx298*K)#

#=94.4*mol#

So, for each man, we need AT LEAST, #2/3xx94.4*molxx122.55*g*mol^-1=7.71xx10^3*g#, call it #8*kg# per day. For 100 persons, that's about a tonne of oxygen candles daily. I don't think this could be done realistically.

You are free to challenge my calculations and assumptions, but I suspect that oxygen candles were provided to the sailors who manned midget submarines, that is, crews of one or two people, where it might be possible to store about 100 kg of sodium chlorate. The sailors who did this, that is, who entered a war zone in a submersible carrying these kinds of powerful oxidants along with their explosives, were undoubtedly courageous and desperate men.

Peyton Adams · Answer

undefined To compute the mass of NaClO3 required, you would first need to balance the equation for the decomposition of NaClO3, then use stoichiometry to determine the amount of NaClO3 needed to produce the required moles of O2.