How many molecules of hydrogen gas was produced if
5.0 moles of lead was consumed?

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

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.