Question

Study the experimental set up of apparatus shown below.
        

1. State the observation made in the combustion tube as the experiment progressed.
2. Using an equation, explain the change that occurred in the conical flask after a long time.
3. Why was the gas burned at point x?  

Answer 1

1. Black Copper(II)Oxide changes to red brown copper.
2. Ca(OH)_2(aq) + CO_2(g) → CaCO_3(s) + H₂O_(l)
   CaCO_3(s) +H₂O_(l) + CO_2(g) → Ca(HCO₃)_2(aq)
   White precipitate which dissolves in excess CO2
3. To prevent CO from escaping to the atmosphere hence polluting it as it is poisonous.