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A gold sample contains 90%` of gold and the rest copper. How many atoms of gold are present in one gram of this sample of gold? |
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Answer» Mass of pure gold in one gram of the sample =`(1xx90)/(100)=0.9g` No. of moles of gold present`=("Mass of gold")/("Molar atomic mass")=((0.9g))/((0197"g mol"^(-1)))=0.046"mol"` One mole of gold contains atoms=`N_(A)=6.022xx10^(23)` 0.046 mole of gold conatins atoms=`6.022xx10^(23)xx0.046=2.77xx10^(21)` |
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