Question

The following set-up was used by students to demonstrate a certain process.
         

1. Identify the process being investigated. 
2. Name solution C 
3. State the observations expected at the end of the experiment in:-
   Tube A  
   Tube B
4. Account for the observations made in:- 
   Tube A
   Tube B    
5. If the animal was replaced by a potted plant.
   1. What modification would you make in the set-up above? 
   2. Give a reason for your answer in 5 (1) above. 

Answer 1

1. Respiration
2. Calcium hydroxide / lime water
3.  
   1. Tube A- Remains colorless / no change in color
      Rej no change / observation
   2. Tube B- White precipitate formed.
4.  
   1. Tube A-Carbon IV Oxide in air is observed by sodium hydroxide therefore solution C/Calcium hydroxide solution / lime water does not change in color.
   2. Tube B - The animal / rat respires producing carbon (IV) Oxide which passes to tube B and reacts with solution C to form a white precipitate
5.  
   1. The animal / rat respires producing carbon (IV) Oxide which passes to tube B and reacts with solution C to form a white precipitate
   2. The black cloth/paper/alluminium foil prevents light from reaching the plant; therefore preventing photosynthesis from taking place/the plant carries out respiration only.