question about an equation:Na2CO3(aq)+Cu(s)-->Cu(s)CO3(s)+2Na?

Question

In a text there is a note saying that Na2 must be written as 2Na not Na2 (subscript). I don't understand why as it is the same thing. Any help would be appreciated

Answer 1

Becoz Na is a metal. It wont exist as Na2 molecule.

Answer 2

I agree, there is no Na2 , Check the context, Maybe the ewquation is as follows:

Na2CO3 + Cu = 2Na + CuCO2

Odd reaction. This is a simple sustitution of the sodium by copper. By the way, it is unlikely will happen- Anyway, if the sodium molecule is considered monoatomic, this mean that one molecule of sodium is made of one atom of sodium, so it´s Na, not Na2. To balance the equation we mus write 2Na, this mean that we have two molecules of sodium. There are some elements that are diatomic, this mean that two atoms make up for one molecule, such as oxygen O2, nitrogen N2 and we should not write 2O neither 2N.