need help with limiting reagent problem (1 Viewer)

[angmor]

4L of NO2 gas at STP is produced by the reaction of copper metal with conc. nitric acid. Copper(II) nitrate and water are also formed.
calculate the mass of copper that would need to react with the excess nitrica acid to produce this quantity of nitrogen dioxide.


thanks .

 

[Riviet]

Cu + 4HNO₃ -> 2NO₂ + Cu(NO₃)₂ + H₂0

n_NO2=v/22.41
=4/22.41

1 mole of copper reacts to form 2 moles of NO₂

.'. n_Cu= 1/2 x 4/22.41

m_Cu=n.M
=(1/2 x 4/22.41) x 63.5
=5.67g

Hope that helps.

[beaten by LottoX]

 

[angmor]

tyvm...but what does a question mean when it says excess nitric acid? dont i have to try to find the limiting reagent or something?

 

[Riviet]

tyvm...but what does a question mean when it says excess nitric acid? dont i have to try to find the limiting reagent or something?

You only need to worry about limiting reagents when you are given the volume of all the reactants. In this question you are given info on only 1 of the reactants, the excess nitrogen just ensures that all the 4L of nitrogen dioxide gas reacts.