A compound which contains one atom of X and two atoms of y for each three atoms of z is made of mixing 5 gm of x, `1.15 times 10^(23)` atoms of Y and 0.03 mole of Z atoms. Given that only 4.40 gm of compound results. Calculate the atomic weight of Y if atomic weight of X and Z are 60 and 80 respectively.

Explanation

Moles of `x=5/60=1/12=0.083`
Moles of y `=(1.15 times 10^(23))/(6.023 times 10^(23))=0.19`
Moles of z = 0.03
`x+2y+3z rarr xy_(2)z_(3)`
for limiting reagent, 0.83/1=0.083
`0.19/2=0.095, 0.03/3=0.01`
Hence z is limiting reagent
wt of `xy_(2)y_(3)=4.4 gm="moles" times "molecular wt."`
moles of `xy_(2)z_(3)=1/3 times 0.03=0.01`
`300+2m=400 rArr 2m=440-300 rArr m=70`