Why Does Adding Nitric Acid to Copper and Carbon Dioxide Produce Brown Gas?

[Revengeance]

Homework Statement

Difference between nitric acid added to the mixture Copper Oxide + Carbon
and nitric acid added to the mixture Copper + Carbon Dioxide

2. Homework Equations
meteal oxide + carbon ---> metal + carbon dioxide

The Attempt at a Solution

When I added Nitric Acid to the mixture Copper Oxide + Carbon no reaction had occured, when i then added it to copper + Carbon Dioxide (after a reducation reaction) a brown gas had formed, is the reason behind the formation of brown gas due to nitric acid reacting with copper? Or am i completely wrong.

 

[Wee-Lamm]

This is an interesting read, that may help.

https://www.angelo.edu/faculty/kboudrea/demos/copper_HNO3/Cu_HNO3.htm

 

[Borek]

When I added Nitric Acid to the mixture Copper Oxide + Carbon no reaction had occured

Are you sure there were no reaction?

 

[Revengeance]

Are you sure there were no reaction?

Yeah I added a few drops and saw nothing

 

[Wee-Lamm]

Is your Nitric Acid of the Dilute or Concentrated variety?

You may have to heat the mixture slightly, I hope you are using a Fume hood for proper ventilation.

 

[Revengeance]

Is your Nitric Acid of the Dilute or Concentrated variety?

You may have to heat the mixture slightly, I hope you are using a Fume hood for proper ventilation.

it is concentrated

 

[Wee-Lamm]

What is your source of copper?

http://cldfacility.rutgers.edu/content/coin-operated-red-white-and-blue-reaction

 

[Borek]

Yeah I added a few drops and saw nothing

"Saw nothing" and "there were no reaction" are two different things. In some reactions there are obvious signs that something is going on (evolving gas), in some the effect is much more subtle.

 

[Revengeance]

"Saw nothing" and "there were no reaction" are two different things. In some reactions there are obvious
signs that something is going on (evolving gas), in some the effect is much more subtle.

Yeah thanks that is a key part in my observations

One more question, it was confirmed by my teacher that after the heating of the mixture (copper oxide + carbon) , there was copper + carbon dioxide, i have a question that asks to to write the balanced chemical equation for the reaction which took place when the concentrated nitric acid was added to the solid mixture after heating, would this be nitric acid + copper ?

Or something else, because nitric acid + copper + carbon dioxide doesn't really make sense to me.

 

[Borek]

I am not sure I follow you, but there two reactions here - one is between copper (or copper oxide, depending on the sample) and the nitric acid, the other between carbon and the nitric acid.

 

[Wee-Lamm]

A balanced equation will account for every atom that was present before the reaction, and every atom that was present after the reaction. This ensures that our equation doesn't allow any atoms to magically appear or disappear during the reaction. This will resemble the 2nd criteria in the problem description, in your opening post. meteal oxide + carbon ---> metal + carbon dioxide

2 examples could be;

OH -> H+O
CuCO3 -> CuO +CO2 I'll let you figure out what happened to the Nitric Acid you added to the mixture but Borek's last post is a good hint.

 

[Revengeance]

A balanced equation will account for every atom that was present before the reaction, and every atom that was present after the reaction. This ensures that our equation doesn't allow any atoms to magically appear or disappear during the reaction. This will resemble the 2nd criteria in the problem description, in your opening post. meteal oxide + carbon ---> metal + carbon dioxide

2 examples could be;

OH -> H+O
CuCO3 -> CuO +CO2 I'll let you figure out what happened to the Nitric Acid you added to the mixture but Borek's last post is a good hint.

Ok but the question says when concentrated nitric acid was added to the solid mixture after heating

So wouldn't it just be copper + nitric acid?

 

[Wee-Lamm]

Ok but the question says when concentrated nitric acid was added to the solid mixture after heating

So wouldn't it just be copper + nitric acid?

What happened to the CO2?

 

[Revengeance]

What happened to the CO2?

Oh, so the heated mixture is copper + CO2?

But if it was like that how would nitric acid be added.

 

[Wee-Lamm]

Yeah thanks that is a key part in my observations

One more question, it was confirmed by my teacher that after the heating of the mixture (copper oxide + carbon) , there was copper + carbon dioxide, i have a question that asks to to write the balanced chemical equation for the reaction which took place when the concentrated nitric acid was added to the solid mixture after heating, would this be nitric acid + copper ?
Or something else, because nitric acid + copper + carbon dioxide doesn't really make sense to me.

Nitric Acid = NCO3

Did you also add water after adding the Nitric Acid, to make the mixture turn blue?