[tomkoolen]

Hello everyone, I am having some trouble with the following problem:

Sulfur dioxide gas can be prepared in the laboratory by heating a mixture of
copper turnings and concentrated sulfuric acid in a suitable flask.

Derive a balanced ionic equation for this reaction using the half-reactions
that take place.

My work so far:
The half-reactions are:
2 Cu <-> 2 Cu+ + 2 e-
SO4(2-) + H2O + 2e- <-> SO3(2-) + 2 OH-

Now if I add these half-reactions, I obtain Cu2SO3, which is unfortunately not the compound asked for. Can anyone help?

Thanks in advance,
Tom Koolen

[Borek]

Are you sure it is Cu⁺ that is produced, and not Cu²⁺?

Why don't you try to balance SO₄^2- SO₂?

[Big-Daddy]

I don't get what you're doing ... if SO2 is being produced, write the equation for SO₄^2- to SO₂ and then combine it with Cu -> Cu²⁺ + 2e^- which you've already got. You should find you don't even need to balance the electrons, as they are the same number - just add directly.

[9-92-6-19]

Cu + H₂SO₄ --> Cu²⁺ + SO₄^2- + 2H⁺ + 2e^-


From there balance resulting H⁺ and e^- with more H₂SO₄

[Borek]

Cu + H₂SO₄ --> Cu²⁺ + SO₄^2- + 2H⁺ + 2e^-


From there balance resulting H⁺ and e^- with more H₂SO₄

?

Where is the SO₂?

What are e^- for? Is this intended to be a full reaction, or a half reaction?

[Big-Daddy]

Cu + H₂SO₄ --> Cu²⁺ + SO₄^2- + 2H⁺ + 2e^-


From there balance resulting H⁺ and e^- with more H₂SO₄

Firstly, H₂SO₄ is assumed identical  to H⁺ + SO₄^2- already for the purposes of this reaction. You can assume this has already happened to completion and that you're working with the sulphate and H⁺ ions now.

Secondly, final reactions cannot have electrons in them ...

[lrinvest]

how to do this?

[Borek]

how to do this?

How to do what?