Atoms to Formula Units: Calculate Al2O3 Moles

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SUMMARY

The discussion focuses on calculating the moles of aluminum oxide (Al2O3) from a given number of total atoms, specifically 8.29×10^25. The solution involves two steps: first, determining the number of formula units using Avogadro's number (6.02×10^23) and then calculating the moles of Al2O3. The correct final answer is 27.5 moles, derived from recognizing that each formula unit of Al2O3 consists of 2 aluminum (Al) atoms and 3 oxygen (O) atoms, thus requiring a proper ratio of Al and O in the calculations.

PREREQUISITES
  • Understanding of Avogadro's number (6.02×10^23)
  • Basic knowledge of chemical formulas and mole calculations
  • Familiarity with stoichiometry in chemical reactions
  • Ability to perform unit conversions in chemistry
NEXT STEPS
  • Study the concept of stoichiometry in chemical equations
  • Learn about mole-to-mass conversions in chemistry
  • Explore the significance of Avogadro's number in chemical calculations
  • Practice calculating moles from different chemical compounds
USEFUL FOR

Chemistry students, educators, and anyone involved in chemical calculations or stoichiometry will benefit from this discussion.

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Homework Statement


A sample of aluminum oxide, Al2O3(s), contains 8.29*10^25 total atoms. Calculate the amount in moles of aluminum oxide in the sample. Hint: This is a two-step problem. Calculate the number of formula units first.

Homework Equations



N=N × N_{A}

The Attempt at a Solution


8.29×10^{25} ( 1 atm/ 6.02 × 10^{23})
=1.38× 10 ^{2}

The question mention that it has two steps but I do not know how..
The correct answer is 27.5 mol ...
 
Physics news on Phys.org
One molecule of aluminum oxide has 2 Al atoms and 3 O atoms. The sample contains 8.29*10^25 atoms, which includes both Al and O. This sample also represents X moles of aluminum oxide. Hint: figure out the proportions of Al and O in aluminum oxide.
 

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