AP EAPCET 20-Aug-2021 Shift 1 Paper

Mass of sample of alloy =12g
% of metal X in sample =20
∴ If x is the mass of metal X in sample

x

12

×100=20
⇒x=2.4g
If y is the mass of metal Y in sample, then
y=12−2.4=9.6g
Number of atoms of X =

6.022×1023×2.4

40

=361×1022
Ratio of atoms of X and Y=2:5
Number of atoms of Y=

361×1022×5

2

=9.025×1022 atoms
9.025×1022 atoms of Y are present in 9.6g.
6.022×1023 atoms of Y are present in

95

9.025×1022

×6.022×1023=64g
Atomic mass of Y=64‌amu.