What is the mass of sulfate of ammonia that can be obtained from 1.00 tonne of sulfuric acid and 0.500 tonne of ammonia?

1 Answer
Apr 22, 2017

Answer:

Well, we need (i) a stoichiometric equation..............and get #B#.

Explanation:

#2NH_3 + H_2SO_4 rarr (NH_4)_2SO_4#.

Two equiv of ammonia react with one equiv sulfuric acid to give one equiv of the salt, #"ammonium sulfate"#. This is an acid-base reaction.........

And so we calculate the molar equivalence of each of the given reagents.......(ii)

#"Moles of sulfuric acid"=(1000xx10^3*g)/(98.08*g*mol^-1)=10.2xx10^3*mol.#

#"Moles of ammonia"=(500xx10^3*g)/(17.03*g*mol^-1)=29.4xx10^3*mol.#

Now clearly, there is a STOICHIOMETRIC excess of ammonia. Agreed? And the limiting reagent is sulfuric acid. At equivalence, there are #10.2xx10^3*mol# of ammonium sulfate.........

This represents a mass of #10.2xx10^3*molxx132.14*g*mol^-1#

#=1348*kg#, i.e. #1.35*"tonne"#, and so you know which option.......

Now this is a hard question for an A-level student, or even a 1st year chem student. But all I have done is to (i) write the stoichiometric equation, and (ii) calculated the molar equivalence; and this is made difficult here because they quote mass in #"TONNES"# rather than the more familiar #"grams"# (and this is why I converted the mass to grams initially - chemists typically work in gram quantities). I agree that this is a lot of work for a multiple choice question.

As to the second part of your question, ammonia, is a BASIC species. It undergoes an acid base reaction in water according to the following reaction.........

#NH_3+H_2OrightleftharpoonsNH_4^(+) + HO^-#;

were I do to this with hydrochloric acid, I would get:

#NH_3(aq) + HCl(aq) rarr NH_4Cl(aq)#

SOME POINTS TO CONSIDER............

#"Ammonium chloride"# or #"ammonium sulfate"# ARE SALTS............

#"Ammonia"# is a colourless gas, #NH_3(g)#, with a foul, penetrating odour. We can make aqueous solution of ammonia (ammonia gas has substantial water solubility), but the dominant species in solution is the free-base, #NH_3#, and there only small equilibrium quantities of ammonium ion. This is knowledge that I would expect of a 1st year university student, or of a good A level student.