NaCl + CuSO4

to write the product would i just do double replacement to get

Na2SO4 + CuCl2

so the whole thing would be

2NaCl + CuSO4 --> Na2SO4 + CuCl2

Yes, the reaction, if it occurred, is a double replacement and you have written it correctly and balanced it. HOWEVER, it will not react and you should have written it like this.

NaCl + CuCO4 ==> No reaction or as NR.
Reactions occur for one of four reasons.
1. a gas is formed. Neither of the products is a gas so this one is out.
2. a precipitate is formed. Both of the products you wrote are soluble so this one is out.
3. A slightly ionized substance is formed. Both CuCl2 and Na2SO4 are strong electrolytes so this one is out.
4. Some oxidation/reduction reactions but this is not a redox reaction so this one is out.
So, NR.

okay how can you tell if they are strong electrolytes or the oxidation one

i understand the others

Strong electrolytes versus weak electrolytes. The question, really is how can you know a weak electrolyte. Look in a set of tables called ionization constants. There is a table for weak acids and another one for weak bases. If the material is listed there it is a weak electrolyte. If not it is a strong electrolyte. Most salts are strong electrolytes. Most organic compounds are weak electrolytes or non-electrolytes. On the subject of redox reactions, you haven't covered those yet, I don't expect, so don't worry about them until they arrive. The other three will get you through most reactions, even some of those that are redox reactions.

Ca(s) + Br2(l) --> CaBr2 is synthesis

my teacher also said that the cause of the reaction is stable electron configuration

is that the same thing as the electrolytes one

Answered above as a separate post.

To determine the products of a chemical reaction, you can use the process of double replacement, also known as metathesis. In this case, you are given the reactants NaCl (sodium chloride) and CuSO4 (copper(II) sulfate).

In a double replacement reaction, the positive ions (cations) of the two compounds swap places with each other.

So, first, you need to identify the positive ions of each compound:
- NaCl: The cation is Na+ (sodium ion)
- CuSO4: The cation is Cu2+ (copper(II) ion)

Now, you swap the cations between the compounds, giving you the potential products:
- Na2SO4 (sodium sulfate)
- CuCl2 (copper(II) chloride)

So, the potential product of the reaction can be written as:
2NaCl + CuSO4 --> Na2SO4 + CuCl2

However, it's important to note that this is a theoretical prediction based on the rules of double replacement reactions. In reality, the reaction may not occur or might produce additional products depending on various factors like reaction conditions or chemical stability. Experimental verification is always necessary to confirm the products of a reaction.