Answer:
5 molecules of H₂O can be produced
0.5 molecules of O₂ did not reacted
Explanation:
The reaction is: 2H₂(g) + O₂(g) → 2H₂O (g)
Firstly we determine the limiting reactant:
2 moles of hydrogen need 1 mol of oxygen to react
We must know the moles of each.
6.02ₓ10²³ molecules is 1 mol
3 molecules are ____ 3 /6.02ₓ10²³ = 4.98×10⁻²⁴ moles O₂
5 molecules are ____ 5 / 6.02ₓ10²³ = 8.30×10⁻²⁴ moles H₂
2 moles of H₂ need 1 mol of O₂
Then 8.30×10⁻²⁴ moles of H₂ must need (8.30×10⁻²⁴ .1) / 2 = 4.15×10⁻²⁴ moles O₂. It is ok, because I have 4.98×10⁻²⁴ moles O₂. Oxygen is the reagent in excess, so the limiting is the H₂
1 moles of O₂ needs 2 moles of H₂ to react
Then, 4.98×10⁻²⁴ moles of O₂ must need (4.98×10⁻²⁴ .2) / 1 =9.96×10⁻²⁴ moles of H₂, we don't have enough H₂
So, in the reaction ratio is 2:2.
8.30×10⁻²⁴ moles of H₂ will produce 8.30×10⁻²⁴ moles H₂O
1 mol has 6.02×10²³ molecules
8.30×10⁻²⁴ must have (8.30×10⁻²⁴ . NA) = 5 molecules
The reagent in excess is the O₂. These means that there is oxygen that has not reacted.
We have 4.98×10⁻²⁴ moles O₂ and we used 4.15×10⁻²⁴ moles.
(4.98×10⁻²⁴ - 4.15×10⁻²⁴) = 0.83×10⁻²⁴ moles of oxgen hasn't reacted.
1 mol is contained by NA molecules
0.83×10⁻²⁴ moles are contained by (0.83×10⁻²⁴ . 6.02×10²³) = 0.5 molecules
