The composition in mol% of the elements are :
Given data :
Weight percentage of copper alloy = 7.7 wt %
Assume weight of alloy = 100 grams
mass of Al₂O₃ in alloy = 7.7 gm
Mass of Cu in alloy = 100 - 7.7 = 92.3 gm
First step : calculate the mole of elements
i) moles of Al₂O₃ in alloy
= mass of Al₂O₃ in alloy / Atomic mass of Al₂O₃
= 7.7 gm / 102 gm/mol
= 0.075 mol
ii) moles of Cu in alloy
= mass of Cu in alloy / Atomic mass of Cu
= 92.3 gm / 63.5 gm/mol
= 1.45 mol
Therefore the total number of moles in the alloy = 0.075 + 1.45 = 1.525
Next step : Determine the mole percentages
i) Mole percentage of Al₂O₃ in alloy
= ( 0.075 ) / 1.525 * 100
= 4.91%
ii) Mole percentage of Cu in alloy
= ( 1.45 ) / 1.525 * 100
= 95.08%
Hence we can conclude that The composition in mol% of the elements are : 4.91% of Al₂O₃ in alloy and 95.08% of Cu in alloy.
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