About 6.5x10^22 molecules.
(5g C2H5OH)x(1 mol C2H5OH/46g C2H5OH)x(6.02x10^23 molecules C2H5OH/1 mol C2H5OH)=(3.01E24)/46=6.5x10^22.
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Answer:
Pb: 22.4 at%
Sn: 77.6 at%
Explanation:
It is possible to find at% of Pb and Sn converting mass in moles using molar mass assuming a basis of 100g, thus:
Pb: 33.5g × (1mol / 207.2g) = <em>0.1617mol</em>
Sn: 66.5g × (1mol / 118.7g) = <em>0.5602mol</em>
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Total moles: 0.1617mol + 0.5602mol = 0.7219mol
Composition in at%:
Pb: 0.1617mol / 0.7219mol × 100 = <em>22.4 at%</em>
Sn: 0.5602mol / 0.7219mol × 100 = <em>77.6 at%</em>
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I hope it helps!
