Balance the Chemical Equation

[student34]

Homework Statement

A student performs a single replacement reaction by dipping a strip of copper metal, Cu(s), into an aqueous solution of silver nitrate, AgN0₃(aq), to produce silver, Ag(s). Write the balanced equation.

Homework Equations

The Attempt at a Solution

The answer has, 2AgN0₃(aq) + Cu(s) = 2Ag(s) + Cu(N0₃)₂(aq).

This only makes sense to me if it is copper II metal. Doesn't it have to specify? How else would I know?

I know that there is some naming rule that says something about if there is nothing specified, then it is one or the other. But I have seen copper II specified before.

 

[Bystander]

How else would I know?

This is among a whole lot of other information that just has to stick in your memory. "The plus II oxidation state for Cu" is the one you commonly encounter. There isn't any convincing argument for stability of nine electrons in the 4s and 3d orbitals (Cu⁺²) being greater than that of ten electrons (Cu⁺), so don't feel you've missed seeing something that should be obvious to you --- it isn't obvious to anyone.

 

[student34]

This is among a whole lot of other information that just has to stick in your memory. "The plus II oxidation state for Cu" is the one you commonly encounter. There isn't any convincing argument for stability of nine electrons in the 4s and 3d orbitals (Cu⁺²) being greater than that of ten electrons (Cu⁺), so don't feel you've missed seeing something that should be obvious to you --- it isn't obvious to anyone.

Shouldn't they have put "copper II" instead of just "copper"? That is what throws me off.

 

[Borek]

No, no need for that. Cu(I) is quite rare. You may expect Cu(I) in questions related to some quite specific copper chemistry, but not when it comes to a general copper reaction in the solution.

 

[DeeNos]

I would first clarify with the student what they mean by "copper metal". In chemistry, there are two common forms of copper: copper(I) and copper(II). Copper(I) is usually referred to as "copper metal" while copper(II) is commonly called "copper(II) metal" or "copper(II) ion". It is important to specify which form of copper is being used in the reaction because it affects the overall charge and reactivity of the compounds involved.

If the student is referring to copper(II) metal, then the equation they have provided is correct. However, if they are referring to copper(I) metal, then the equation should be 2AgNO3(aq) + 2Cu(s) = 2Ag(s) + 2CuNO3(aq). This is because copper(I) has a +1 charge, while copper(II) has a +2 charge.

In general, it is important to specify the oxidation state of each chemical species in a chemical equation to ensure accuracy and clarity. This can be done by using Roman numerals in parentheses after the element's name, such as copper(II) or by using the appropriate prefixes, such as di- for two and tri- for three.

In summary, to write a balanced chemical equation, it is important to specify the oxidation state of each element and to clarify any potential confusion with naming conventions.