Bell metal contains 80% copper . The mas...

Bell metal contains 80% copper . The mass of Bell metal which contain `1.5 xx 10^(20)` atoms of copper is (Cu = 64)

A

2mg

B

20mg

C

40mg

D

12.8mg

Verified by Experts

The correct Answer is:

B

100 gm = 80 g Cu
100 gm = `(80)/(63.5)xx6xx10^(23)` atoms of Cu
`? rarr1.5xx10^(20)` atoms of Cu
`=(6xx10^(23)xx15xx10^(-3))/(1.5xx10^(20))=60`

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