Question 5.SP.22: Using the balanced equation, 3H2(g) + N2(g)→ 2NH3( g), calcu...
Using the balanced equation 3H_{2}(g) + N_{2}(g) \longrightarrow 2NH_{3}( g) calculate the number of moles of product formed from 5.0 moles of H_{2} and 3.0 moles of N_{2}.
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[1] Determine the limiting reactant as in Sample Problem 5.21.
• Identify H_{2} as the original quantity and use the mole ratio from the balanced equation as a conversion factor to calculate how much N_{2}. is needed for complete reaction.
\begin{matrix} & & \text{mole–mole conversion factor}& &\\ \\ 5.0 \cancel{mol } H_{2} &\times & \frac{\text{1 mol }N_{2}}{3 \cancel{ mol }{}H_{2}} &= & \text{1.7 mol } N_{2} \text{ needed }\end{matrix}
• Since the amount of N_{2} present is greater than what is needed, N_{2} is present in excess and H_{2} is the limiting reactant.
[2] Convert the number of moles of limiting reactant to the number of moles of product using a mole–mole conversion factor.
\begin{matrix} & & \text{mole–moleconversion factor}& &\\ \\ 5.0 \cancel{mol } H_{2} &\times & \frac{\text{2 mol }NH_{3}}{3 \cancel{ mol }H_{2}} &= & \text{3.3 mol } NH_{3} \text{ formed } \\ &&&& Answer\end{matrix}