Question

Question #fc962

Answer 1

14,5% of Zn

Explanation:

From the gasses ideal Law and by consedering that 760 mmHg = 1 atm we have `n(H_2) = (PV)/(RT)= (1 atm 0,328L)/ ((0,082 (L atm )/(mol K)) 300K)= 0,0133 mol`.

These mol of `H_2` comes from the reaction:
`Zn + H_2SO_4 = ZnSO_4 + H_2`
from which you see that need 1 mol of Zn to form 1 mol of `H_2` so need 0,0133 mol of Zn to form 0,0133 mol of `H_2`
If 1 mol of atoms of Zn weigh 65,4 g, 0,0133 mol of Zn weigh 0,872 g that in 6 g of alloy are 14,5% of the brass.
That is a theoretical reaction because if Zn react quite quantitatively with sulfuric acid, Cu could reacts partially especially if sulfuric acid is warm and concentrated.