Answer : The mass percent of Al in the alloy is 85.9 %.
Explanation : Given,
Mass of sample of an alloy = 1.1181 g
Mass of
= 0.1068 g
Molar mass of
= 2 g/mol
Molar mass of
= 27 g/mol
First we have to calculate the moles of
.
![\text{Moles of }H_2=\frac{\text{Given mass }H_2}{\text{Molar mass }H_2}](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20of%20%7DH_2%3D%5Cfrac%7B%5Ctext%7BGiven%20mass%20%7DH_2%7D%7B%5Ctext%7BMolar%20mass%20%7DH_2%7D)
![\text{Moles of }H_2=\frac{0.1068g}{2g/mol}=0.0534mol](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20of%20%7DH_2%3D%5Cfrac%7B0.1068g%7D%7B2g%2Fmol%7D%3D0.0534mol)
Now we have to calculate the moles of ![Al](https://tex.z-dn.net/?f=Al)
The balanced chemical equation is:
![2Al+2NaOH+6H_2O\rightarrow 2Na[Al(OH)_4]+3H_2](https://tex.z-dn.net/?f=2Al%2B2NaOH%2B6H_2O%5Crightarrow%202Na%5BAl%28OH%29_4%5D%2B3H_2)
From the reaction, we conclude that
As, 3 moles of
produced from 2 moles of ![Al](https://tex.z-dn.net/?f=Al)
So, 0.0534 mole of
produced from
mole of ![CaCl_2](https://tex.z-dn.net/?f=CaCl_2)
Now we have to calculate the mass of ![Al](https://tex.z-dn.net/?f=Al)
![\text{ Mass of }Al=\text{ Moles of }Al\times \text{ Molar mass of }Al](https://tex.z-dn.net/?f=%5Ctext%7B%20Mass%20of%20%7DAl%3D%5Ctext%7B%20Moles%20of%20%7DAl%5Ctimes%20%5Ctext%7B%20Molar%20mass%20of%20%7DAl)
![\text{ Mass of }Al=(0.0356moles)\times (27g/mole)=0.9612g](https://tex.z-dn.net/?f=%5Ctext%7B%20Mass%20of%20%7DAl%3D%280.0356moles%29%5Ctimes%20%2827g%2Fmole%29%3D0.9612g)
Now we have to calculate the mass percent of Al in the alloy.
Mass percent of Al in alloy = ![\frac{\text{Mass of Al}}{\text{Mass of sample of an alloy}}\times 100](https://tex.z-dn.net/?f=%5Cfrac%7B%5Ctext%7BMass%20of%20Al%7D%7D%7B%5Ctext%7BMass%20of%20sample%20of%20an%20alloy%7D%7D%5Ctimes%20100)
Mass percent of Al in alloy = ![\frac{0.9612g}{1.1181g}\times 100](https://tex.z-dn.net/?f=%5Cfrac%7B0.9612g%7D%7B1.1181g%7D%5Ctimes%20100)
Mass percent of Al in alloy = 85.9%
Therefore, the mass percent of Al in the alloy is 85.9 %.