Question

If the reaction of 9.87 moles of potassium with excess hydrobromic acid produced a 79.8% yield of hydrogen gas, what was the actual yield of hydrogen gas? unbalanced equation: k + hbr kbr + h2 7.88 mol h2 5.74 mol h2 4.94 mol h2 3.94 mol h2

Answer 1

Answer is: 3,94 mol of hydrogen gas.
Chemical reaction: 2K + 2HBr → 2KBr + H₂.
n(K) = 9,87 mol.
from reaction: n(K) : n(H₂) = 2 : 1.
9,87 mol : n(H₂) = 2 : 1.
n(H₂) = 4,935 mol at 100% of reaction.
n(H₂) = 4,395 mol · 0,798 = 3,938 mol.
n - amount of substance.