Calculate how many moles of NH3 form when 3.55 moles of N2H4 completely react according to the equation: 3N2H4 (l) ---> 4NH3 (g) + N2 (g) ?

1 Answer
Jun 15, 2017

Answer:

#4.73# #"mol NH"_3#

Explanation:

What we're doing here is calculating basic mole-mole relationships, something that you'll be doing quite a bit!

The steps to solving mole-mole problems like this are

  • write the balanced chemical equation for the reaction (this is given)

  • divide the number of moles of the given known substance (#3.55#) by that substance's coefficient in the chemical equation (#3#)

  • multiply that number by the coefficient of the substance you're trying to find (#4#)

Using simple dimensional analysis, it looks like this:

#3.55cancel("mol N"_2"H"_4)(larr "given amount")((4"mol NH"_3("coefficient"))/(3cancel("mol N"_2"H"_4)("coefficient")))#

#= color(red)(4.73# #color(red)("mol NH"_3#

rounded to #3# significant figures, the amount given in the problem.

Thus, if the reaction goes to completion, #3.55# moles of #"N"_2"H"_4# will yield #color(red)(4.73# moles of #"NH"_3#.