Calculate the moles of nitrogen produced by the reaction of 1.2mol of ammonium perchlorate.

Question

Ammonium perchlorate NH4ClO4

 is a powerful solid rocket fuel, used in the Space Shuttle boosters. It decomposes into nitrogen N2

 gas, chlorine Cl2

gas, oxygen O2

 gas and water vapor, releasing a great deal of energy. Calculate the moles of nitrogen produced by the reaction of 1.2mol

 of ammonium perchlorate. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits. 

Answer 1

Hi Giulianna C.,

All you really need to do is to first balance the decomposition reaction:

1 NH4ClO4 = 2 H2O + 1 O2 +(1/2)Cl2 + (1/2)N2 .

Why these species? -- Those Cl-O bonds are kind of weak, so when they rearrange in the reaction they release energy. Also, especially the N2 formation releases heat -- that's a really strong bond! To balance, since there are NO other species with H in, they all go into H2O. Then the rest of the O must go into O2, and so on.

So you see what the molar numbers (coefficients of the balanced reaction) are, you should be able to ratio it out, since 1 --> (1/2), then what does 1.2 --> ?

-- Cheers, --Mr. d.

P.S. Do you understand why forming a strong bond releases heat? Unlike putting something like a house together, which requires putting in a lot of work to accomplish(!), putting a bond together just means allowing two atoms to approach each other and share electrons. When they do that, they fall into an energy "pit" -- they can't be easily separated, unless you pump energy back into them to break the bond! The energy depth of that "pit" is the energy that is released to the surroundings when the atoms make their bond. They have to get rid of it, or the bond couldn't form! They would bounce apart again! But if they release it as heat, and that is dissipated to the surroundings, then it's "gone", and the bond stays, well, bonded. The idea that the energy, as heat, goes elsewhere and doesn't prefer to come back and disrupt the bond, is part of the idea of thermodynamics, which you may study later.