Absolutely! Let’s solve each problem step by step using
mole-to-mole stoichiometry. This means we use the
coefficients in the balanced chemical equation as mole ratios to convert between moles of one substance and moles of another.
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Problem 1:
Equation:
2 Al + 6 HCl → 2 AlCl₃ + 3 H₂
#### a. Find the number of moles of Al used to produce 9.9 moles of H₂.
From the equation:
2 mol Al : 3 mol H₂
Set up a proportion:
> Moles of Al = (9.9 mol H₂) × (2 mol Al / 3 mol H₂)
> = (9.9 × 2) / 3
> = 19.8 / 3
> =
6.6 moles of Al
✔ Answer: 6.6 moles of Al
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#### b. Find the number of moles of HCl used to produce 1.11 moles of AlCl₃.
From the equation:
6 mol HCl : 2 mol AlCl₃
> Moles of HCl = (1.11 mol AlCl₃) × (6 mol HCl / 2 mol AlCl₃)
> = (1.11 × 6) / 2
> = 6.66 / 2
> =
3.33 moles of HCl
✔ Answer: 3.33 moles of HCl
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#### c. Find the number of moles of AlCl₃ produced along with 0.0757 moles of H₂.
From the equation:
2 mol AlCl₃ : 3 mol H₂
> Moles of AlCl₃ = (0.0757 mol H₂) × (2 mol AlCl₃ / 3 mol H₂)
> = (0.0757 × 2) / 3
> = 0.1514 / 3
> ≈
0.0505 moles of AlCl₃
✔ Answer: 0.0505 moles of AlCl₃
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Problem 2:
Equation:
2 Li + F₂ → 2 LiF
How many moles of lithium fluoride can be produced with 2.17 mol of fluorine?
From the equation:
1 mol F₂ : 2 mol LiF
> Moles of LiF = (2.17 mol F₂) × (2 mol LiF / 1 mol F₂)
> = 2.17 × 2
> =
4.34 moles of LiF
✔ Answer: 4.34 moles of LiF
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Problem 3:
Equation:
2 CuO → 2 Cu + O₂
How much copper is produced if 0.663 moles of oxygen is given off?
From the equation:
2 mol Cu : 1 mol O₂
> Moles of Cu = (0.663 mol O₂) × (2 mol Cu / 1 mol O₂)
> = 0.663 × 2
> =
1.326 moles of Cu
✔ Answer: 1.326 moles of Cu
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Problem 4:
Equation:
C₆H₁₂O₆ (s) → 2 C₂H₅OH (l) + 2 CO₂ (g)
If 17.5 moles of ethanol were produced, how many moles of glucose were there initially?
From the equation:
1 mol C₆H₁₂O₆ : 2 mol C₂H₅OH
> Moles of glucose = (17.5 mol ethanol) × (1 mol glucose / 2 mol ethanol)
> = 17.5 / 2
> =
8.75 moles of glucose
✔ Answer: 8.75 moles of glucose
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Problem 5:
Equation:
Zn (s) + 2 HCl (aq) → H₂ (g) + ZnCl₂ (aq)
Calculate the moles of HCl needed to react completely with 8.25 moles of zinc.
From the equation:
1 mol Zn : 2 mol HCl
> Moles of HCl = (8.25 mol Zn) × (2 mol HCl / 1 mol Zn)
> = 8.25 × 2
> =
16.5 moles of HCl
✔ Answer: 16.5 moles of HCl
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##
✔ Final Answers Summary:
1. a.
6.6 mol Al
b.
3.33 mol HCl
c.
0.0505 mol AlCl₃
2.
4.34 mol LiF
3.
1.326 mol Cu
4.
8.75 mol glucose
5.
16.5 mol HCl
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Let me know if you’d like to see these solved with dimensional analysis setup or need help with mass-to-mole conversions next!
Parent Tip: Review the logic above to help your child master the concept of chemistry mole worksheet.
