Chemistry Stoichiometry SZABMU 2024
PMDC Verified Question 8 of 105
\( \text{N}_{2(g)} + 3\text{H}_{2(g)} \rightarrow 2\text{NH}_{3(g)} \)

How many moles of \( \text{N}_2 \) required to manufacture 8 moles of \( \text{NH}_3 \)?
A
2.5 moles
B
4 moles
C
3.5 moles
D
5 moles
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 4 moles
Concept:

The coefficients of a balanced chemical equation dictate the strict stoichiometric proportionality between reactants and products.

Formula:

$$ \frac{\text{Moles of N}_2}{\text{Coefficient of N}_2} = \frac{\text{Moles of NH}_3}{\text{Coefficient of NH}_3} $$

Solution:

  • The balanced equation (Haber Process) shows that 1 mole of Nitrogen gas produces 2 moles of Ammonia. (A 1:2 ratio).


  • We want to manufacture 8 moles of Ammonia.


  • Set up the ratio: \( \frac{1}{2} = \frac{x}{8} \).


  • Multiply both sides by 8: \( x = 8 / 2 = 4 \).


  • Therefore, exactly 4 moles of Nitrogen are required.


Why other options are incorrect:

  • 2.5, 3.5, 5 moles: These are random distractors that do not follow the strict 1:2 molar relationship dictated by the balanced equation.

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