when powdered zinc is heated with sulfur, a violent reaction occurs, and zinc sulfide forms:
$\text{zn}(s) + \text{s}_8(s) \
ightarrow \text{zns}(s)$ unbalanced

some of the reactants also combine with oxygen in air to form zinc oxide and sulfur dioxide. when 83.2 g of zn reacts with 52.4 g of $\text{s}_8$, 109.2 g of zns forms.

part 1 of 3
what is the percent yield of zns? be sure your answer has the correct number of significant figures.

part 2 of 3
if all the remaining reactants combine with oxygen, how many grams of zno form? be sure your answer has the correct number of significant figures.

part 3 of 3
if all the remaining reactants combine with oxygen, how many grams of $\text{so}_2$ form? be sure your answer has the correct number of significant figures.

Question

when powdered zinc is heated with sulfur, a violent reaction occurs, and zinc sulfide forms:
$\text{zn}(s) + \text{s}_8(s) \
ightarrow \text{zns}(s)$ unbalanced

some of the reactants also combine with oxygen in air to form zinc oxide and sulfur dioxide. when 83.2 g of zn reacts with 52.4 g of $\text{s}_8$, 109.2 g of zns forms.

part 1 of 3
what is the percent yield of zns? be sure your answer has the correct number of significant figures.

part 2 of 3
if all the remaining reactants combine with oxygen, how many grams of zno form? be sure your answer has the correct number of significant figures.

part 3 of 3
if all the remaining reactants combine with oxygen, how many grams of $\text{so}_2$ form? be sure your answer has the correct number of significant figures.

Accepted Answer

{ "quality": "clear", "question_count": 3, "skills_matched": [ "step_cot", "explain_then_answer", "tutor", "mastery_adaptive_brevity" ], "needs_drawing": false, "concepts_used": [ "Chemical Equation Balancing", "Limiting Reactant Stoichiometry", "Percent Yield Calculations" ], "new_concepts": [ "Side Reaction Stoichiometry", "Reactant Consumption Analysis" ], "current_concepts": [ "Chemical Equation Balancing", "Limiting Reactant Stoichiometry", "Percent Yield Calculations", "Side Reaction Stoichiometry", "Reactant Consumption Analysis" ] } ## Balance the main chemical equation Using the *Chemical Equation Balancing* knowledge point $$ 8\text{Zn}(s) + \text{S}_8(s) ightarrow 8\text{ZnS}(s) $$ ## Determine the limiting reactant Using the *Limiting Reactant Stoichiometry* knowledge point $$ \begin{aligned} &M(\text{Zn}) = 65.38\text{ g/mol},\quad M(\text{S}_8) = 256.52\text{ g/mol}\ &n(\text{Zn})_{\text{initial}} = \frac{83.2\text{ g}}{65.38\text{ g/mol}} \approx 1.2726\text{ mol}\ &n(\text{S}_8)_{\text{initial}} = \frac{52.4\text{ g}}{256.52\text{ g/mol}} \approx 0.20427\text{ mol}\ &\frac{n(\text{Zn})_{\text{initial}}}{8} \approx 0.1591\text{ mol},\quad \frac{n(\text{S}_8)_{\text{initial}}}{1} \approx 0.2043\text{ mol}\ &\text{Zn is the limiting reactant.} \end{aligned} $$ ## Calculate the percent yield of ZnS Using the *Percent Yield Calculations* knowledge point $$ \begin{aligned} &n(\text{ZnS})_{\text{theoretical}} = n(\text{Zn})_{\text{initial}} \approx 1.2726\text{ mol}\ &m(\text{ZnS})_{\text{theoretical}} = 1.2726\text{ mol} \times 97.44\text{ g/mol} \approx 124.0\text{ g}\ &\text{Percent Yield} = \frac{109.2\text{ g}}{124.0\text{ g}} \times 100\% \approx 88.1\% \end{aligned} $$ ## Calculate remaining reactants and ZnO formed Using the *Limiting Reactant Stoichiometry* knowledge point $$ \begin{aligned} &n(\text{ZnS})_{\text{actual}} = \frac{109.2\text{ g}}{97.44\text{ g/mol}} \approx 1.1207\text{ mol}\ &n(\text{Zn})_{\text{reacted}} = 1.1207\text{ mol}\ &n(\text{Zn})_{\text{remaining}} = 1.2726\text{ mol} - 1.1207\text{ mol} = 0.1519\text{ mol}\ &2\text{Zn} + \text{O}_2 ightarrow 2\text{ZnO}\ &n(\text{ZnO}) = n(\text{Zn})_{\text{remaining}} = 0.1519\text{ mol}\ &m(\text{ZnO}) = 0.1519\text{ mol} \times 81.38\text{ g/mol} \approx 12.4\text{ g} \end{aligned} $$ ## Calculate remaining sulfur and SO2 formed Using the *Limiting Reactant Stoichiometry* knowledge point $$ \begin{aligned} &n(\text{S}_8)_{\text{reacted}} = \frac{1}{8} \times n(\text{ZnS})_{\text{actual}} = \frac{1.1207\text{ mol}}{8} \approx 0.14009\text{ mol}\ &n(\text{S}_8)_{\text{remaining}} = 0.20427\text{ mol} - 0.14009\text{ mol} = 0.06418\text{ mol}\ &\text{S}_8 + 8\text{O}_2 ightarrow 8\text{SO}_2\ &n(\text{SO}_2) = 8 \times n(\text{S}_8)_{\text{remaining}} = 8 \times 0.06418\text{ mol} = 0.5134\text{ mol}\ &m(\text{SO}_2) = 0.5134\text{ mol} \times 64.06\text{ g/mol} \approx 32.9\text{ g} \end{aligned} $$ ## Question 1 88.1 ## Question 2 12.4 ## Question 3 32.9 { "subject": "Natural Science", "question_type": "Multi-part", "knowledge_point": [ "Natural Science", "Chemistry", "Limiting Reactant Stoichiometry" ] }

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QUESTION IMAGE

Question

Explanation:

Balance the main chemical equation

Determine the limiting reactant

Calculate the percent yield of ZnS

Calculate remaining reactants and ZnO formed

Calculate remaining sulfur and SO2 formed

Answer:

Question 1

Question 2

Question 3