Answer:
6.6 moles.
Explanation:
- It is a stichiometric oriented problem.
- We need to write the balanced chemical equation of the reaction:
Cu + 4HNO₃ → Cu(NO₃)₂ + 2NO₂ + 2H₂O.
- It is clear that 1.0 mole of Cu reacts with 4.0 moles of 4HNO₃ to produce 1.0 mole of Cu(NO₃)₂, 2.0 moles of NO₂, and 2.0 moles of water.
Now, using cross multiplication:
1.0 mole of Cu produces → 2.0 moles of NO₂, from the stichiometry,
∴ 3.3 moles of Cu produces → ??? moles of NO₂.
∴ the number of moles of NO₂ will form when 3.3 moles of Cu are reacted with excess HNO₃ is = (3.3 moles of Cu) (2.0 moles of NO₂) / (1.0 mole of Cu ) = 6.6 moles.
