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Question
A silver ornament of mass ‘m’ gram is polished with gold equivalent to 1% of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.
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Solution
Mass of gold = mg
Mass of gold = `"m"/100`g
Number of atoms of silver = `"Mass"/"Atomic mass" xx "N"_"A"`
= `"m"/100 xx "N"_"A"`
Number of atoms of gold = `"m"/(100 xx 197) xx "N"_"A"`
Ratio of number of atoms of gold to silver = Au : Ag
= `"m"/(100 xx 197) xx "N"_"A" : "m"/108 xx "N"_"A"`
= 108 : 100 × 197
= 108 : 19700
= 1: 182.41
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