Proficient:
1. Use the balanced equation below to answer the following questions:
\[
2 \mathrm{~S}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{SO}_{3}
\]
How much \( \mathrm{O}_{2} \) you will need to use in order to make \( 27 \mathrm{~g} \) of \( \mathrm{SO}_{3} \) ?
a. Identify what you know and what you want to find:
b. Convert mass to moles
Answer
\( \text{Step 2: Apply stoichiometry to calculate moles of O}_{2}\text{: } \frac{3 \mathrm{mol \, O}_{2}}{2 \mathrm{mol \, SO}_3} \cdot \frac{27}{80.0642} \mathrm{mol \, SO}_{3} = \frac{81}{160.1284} \mathrm{mol \, O}_{2}\)
Step 1 ：\( \text{Given: Balanced equation: } 2 \mathrm{S} + 3 \mathrm{O}_{2} \rightarrow 2 \mathrm{SO}_{3}\text{, and } 27 \mathrm{g} \) of \( \mathrm{SO}_{3} \)
Step 2 ：\( \text{Step 1: Convert mass of SO}_{3} \text{ to moles: } \frac{27 \mathrm{g} \, \mathrm{SO}_{3}}{1 \mathrm{mol \, SO}_3 \cdot 80.0642 \mathrm{g \, SO}_3} = \frac{27}{80.0642} \mathrm{mol \, SO}_{3}\)
Step 3 ：\( \text{Step 2: Apply stoichiometry to calculate moles of O}_{2}\text{: } \frac{3 \mathrm{mol \, O}_{2}}{2 \mathrm{mol \, SO}_3} \cdot \frac{27}{80.0642} \mathrm{mol \, SO}_{3} = \frac{81}{160.1284} \mathrm{mol \, O}_{2}\)
