Question

The student's lab manual says to mix some of his Na2CO3 solution with an aqueous solution of copper(II) sulfate (CuSO4)

i What evidence of a chemical reaction would he expect to see? Explain your answer.
ii Write a balanced chemical equation to show the reaction. Include state symbols.
iii What kind of reaction is this?

Answer 1

i When sodium carbonate (Na2CO3) is mixed with an aqueous solution of copper(II) sulfate (CuSO4), the student can expect to see several evidence of a chemical reaction:

Formation of a solid precipitate: When these two solutions are mixed, a solid precipitate of copper(II) carbonate (CuCO3) will form. This is a sign that a chemical reaction has occurred.

Change in color: The reaction between sodium carbonate and copper(II) sulfate will also result in a change in color. The solution may turn a blue or green color, indicating the presence of copper(II) ions.

Release of gases: The reaction between sodium carbonate and copper(II) sulfate may also produce gases, such as carbon dioxide (CO2).

ii The balanced chemical equation for the reaction between sodium carbonate and copper(II) sulfate is:

2Na2CO3(aq) + CuSO4(aq) → 2Na2SO4(aq) + CuCO3(s)

iii This is a double displacement reaction, also known as a metathesis reaction. In this type of reaction, the cations (positively charged ions) and anions (negatively charged ions) of the reactant compounds exchange places to form the products. In this case, the sodium ions (Na+) and the copper ions (Cu2+) exchange places to form sodium sulfate (Na2SO4) and copper carbonate (CuCO3).