Carbinates
DISSCUSION: Carbonates are decomposed by heat into the corresponding oxides and carbon dioxide. The temperature of decomposition depends upon the activity of the metal; that is to say, the more active the metal, the more stable is the carbonate. Thus, the carbonates of sodium and potassium are stable at the highest temperature of a Bunsen burner flame, whereas the carbonates of silver and copper are easily decomposed. In this experiment copper (ii) carbonate will be decomposed at a high temperature, forming copper (ii) oxide and carbon dioxide:
CuCO3(s) arrow CuO(s) + CO2(g)
You will test for the formation of copper (ii) oxide and carbon dioxide. Limewater is a sensitive test for CO2, forming a distinctive milky precipitate:
CO2(g) + Ca(OH)2(aq) arrow CaCO3(s) + H2O(l)
Calcium carbonate is strongly heated until it undergoes thermal decomposition to form calcium oxide and carbon dioxide
CaCO3 CaO + CO2
Other metal carbonates decompose in the same way. Here are the equations for the thermal decomposition of copper carbonate: copper carbonate copper oxide + carbon dioxide
CuCO3 CuO + CO2
Notice that in both examples the products are a metal oxide and carbon dioxide. The carbon dioxide gas can be detected using limewater. Limewater turns cloudy white when carbon dioxide is bubbled through it.
Metals high up in the reactivity series - such as calcium - have carbonates that need a lot of energy to decompose them. Metals low down in the reactivity series - such as copper - have carbonates that are easily decomposed. This is why copper carbonate is often used at school to show these reactions. It is easily decomposed, and its colour change, from green copper carbonate to black copper oxide, is easy to see
Copper Carbonate (CuCO3) is heated up so that a decomposition reaction occurs, with the products being Copper (II) Oxide (CuO) and Carbon Dioxide (CO2). The chemical formula is: CuCO3 --> CuO + CO2. If proper apparatus is set up, the carbon dioxide should
CuCO3(s) arrow CuO(s) + CO2(g)
You will test for the formation of copper (ii) oxide and carbon dioxide. Limewater is a sensitive test for CO2, forming a distinctive milky precipitate:
CO2(g) + Ca(OH)2(aq) arrow CaCO3(s) + H2O(l)
Calcium carbonate is strongly heated until it undergoes thermal decomposition to form calcium oxide and carbon dioxide
CaCO3 CaO + CO2
Other metal carbonates decompose in the same way. Here are the equations for the thermal decomposition of copper carbonate: copper carbonate copper oxide + carbon dioxide
CuCO3 CuO + CO2
Notice that in both examples the products are a metal oxide and carbon dioxide. The carbon dioxide gas can be detected using limewater. Limewater turns cloudy white when carbon dioxide is bubbled through it.
Metals high up in the reactivity series - such as calcium - have carbonates that need a lot of energy to decompose them. Metals low down in the reactivity series - such as copper - have carbonates that are easily decomposed. This is why copper carbonate is often used at school to show these reactions. It is easily decomposed, and its colour change, from green copper carbonate to black copper oxide, is easy to see
Copper Carbonate (CuCO3) is heated up so that a decomposition reaction occurs, with the products being Copper (II) Oxide (CuO) and Carbon Dioxide (CO2). The chemical formula is: CuCO3 --> CuO + CO2. If proper apparatus is set up, the carbon dioxide should