What color change occurs when copper(II) carbonate is heated to form copper(II) oxide and carbon dioxide?

What color change occurs when copper(II) carbonate is heated to form copper(II) oxide and carbon dioxide?

• A. Green to Black
• B. Blue to Black
• C. Green to Blue
• D. White to Green

Answer: (A)

Heating copper(II) carbonate causes it to decompose into copper(II) oxide and carbon dioxide. The color change happens because the green solid CuCO3 becomes black solid CuO when it breaks down and CO2 gas escapes. So you see green turning to black as the carbonate converts to oxide: CuCO3(s) → CuO(s) + CO2(g). The black color of the oxide explains why green-to-black is the correct description. The other color options don’t fit because the products here aren’t blue, white, or green-to-blue; the solid left behind after heating is CuO, which is black.

Heating copper(II) carbonate causes it to decompose into copper(II) oxide and carbon dioxide. The color change happens because the green solid CuCO3 becomes black solid CuO when it breaks down and CO2 gas escapes. So you see green turning to black as the carbonate converts to oxide: CuCO3(s) → CuO(s) + CO2(g). The black color of the oxide explains why green-to-black is the correct description. The other color options don’t fit because the products here aren’t blue, white, or green-to-blue; the solid left behind after heating is CuO, which is black.