# 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) ?

Jun 15, 2017

$4.73$ ${\text{mol NH}}_{3}$

#### 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 ${\text{N"_2"H}}_{4}$ will yield color(red)(4.73 moles of ${\text{NH}}_{3}$.