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

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Discussion Overview

The discussion revolves around the chemical reactions involving nitric acid, copper, and carbon dioxide, specifically comparing the reactions of nitric acid with copper oxide and carbon versus copper and carbon dioxide. Participants explore the formation of a brown gas and the conditions under which reactions occur.

Discussion Character

  • Homework-related
  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant describes observing no reaction when nitric acid was added to a mixture of copper oxide and carbon, raising questions about the nature of the reaction.
  • Another participant suggests that the lack of visible reaction does not necessarily mean no reaction occurred, highlighting the subtlety of some chemical processes.
  • There is a discussion about whether the nitric acid used is dilute or concentrated, with a recommendation to heat the mixture for better results.
  • Participants question the balanced chemical equation for the reaction involving concentrated nitric acid, copper, and carbon dioxide, with some uncertainty about the roles of each component in the reaction.
  • One participant mentions that their teacher confirmed the products of heating copper oxide and carbon are copper and carbon dioxide, prompting further inquiry into the balanced equation when nitric acid is added.
  • There is confusion regarding the presence of carbon dioxide in the reaction and how it interacts with nitric acid.
  • A later reply introduces the idea of adding water to the mixture after nitric acid to produce a blue solution, suggesting additional complexity in the reactions discussed.

Areas of Agreement / Disagreement

Participants express differing views on the reactions that occur when nitric acid is added to the mixtures, with no consensus reached on the exact nature of the reactions or the balanced equations involved.

Contextual Notes

Participants acknowledge the need for careful observation of reactions, the potential for subtle signs of chemical activity, and the importance of balanced equations in representing chemical changes. There are unresolved questions about the interactions between nitric acid, copper, and carbon dioxide.

Revengeance
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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 occurred, 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.
 
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Revengeance said:
When I added Nitric Acid to the mixture Copper Oxide + Carbon no reaction had occurred

Are you sure there were no reaction?
 
Borek said:
Are you sure there were no reaction?
Yeah I added a few drops and saw nothing
 
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.
 
Wee-Lamm said:
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
 
Revengeance said:
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.
 
Borek said:
"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.
 
  • #10
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.
 
  • #11
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.
 
  • #12
Wee-Lamm said:
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?
 
  • #13
Revengeance said:
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?
 
  • #14
Wee-Lamm said:
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.
 
  • #15
Revengeance said:
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?
 

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