Answer:
3.01×10²⁴ molecules of H₂
Explanation:
Reaction that can produce hydrogen gas from Pb can be this:
Pb + H₂S → PbS + H₂
1 mol of Pb can react to 1 mol of H₂S to produce 1 mol of PbS and 1 mol of H₂
Ratio is always 1:1.
In conclussion 5 moles of lead will produce 5 moles of H₂.
Let's apply the NA to count molecules
1 mol contains 6.02×10²³
Then, 5 moles must contain (5 . 6.02×10²³) = 3.01×10²⁴ molecules
