Question

For this question use the balanced equation shown:Mg3N2 + 6 H2O → 3 Mg(OH)2 + 2 NH3How many moles of water are needed if 2 moles of Mg3N2 are used?Group of answer choices1 mole6 moles2 moles3 moles12 moles

Answer 1

Answer:

12 moles of water are needed. (The last option)

Explanation:

1st) From the balanced equation we know that 1 mole of Mg3N2 is used to react with 6 moles of water.

2nd) With the stoichiometry of the balanced reaction and a mathematical rule of three we can calculate the moles of water that are needed when 2 moles of Mg3N2 are used:

$\begin{gathered} 1mol\text{ Mg}_3\text{N}_2-6mol\text{ H}_2\text{O} \\ 2mol\text{ Mg}_3\text{N}_2-x=\frac{2mol\text{ Mg}_3\text{N}_2*6mol\text{ H}_2\text{O}}{1mol\text{ Mg}_3\text{N}_2} \\ x=12mol\text{ H}_2\text{O} \end{gathered}$

So, 12 moles of water are needed.