Answer:
it is required a mass of Zn equal to m= 1.608 gr of Zn
Step-by-step explanation:
Assuming that the hydrogen behaves as an ideal gas ( in reality it has positive deviations from the gas law, but we can neglect the small correction) , then
P*V=n*R*T
n = P*V/(R*T)
where
P= absolute pressure = 775 mmHg = 1.02 atm
T= absolute temperature = 30°C+273 = 303 K
V= volume = 600 mL = 0.6 L
R = ideal gas constant = 0.082 atm*L/(mol*K)
n = number of moles of H₂ gas
replacing values
n = P*V/(R*T) = 1.02 atm*0.6 L/(0.082 atm*L/(mol*K)*303 K) = 0.0246 moles of H₂
from the reaction
Zn + 2 HCl ⇒ ZnCl2 + H2
since 1 mole of H2 requires 1 mole of Zn to react , then
m = nz * M
where
nz = number of moles of zinc = number of moles of H₂ gas = 0.0246 moles
M = molecular weight of zinc = 65.38 gr/mol
m = mass of zinc required
therefore
m= 0.0246 moles * 65.38 gr/mol = 1.608 gr of Zn
m= 1.608 gr of Zn