ENDOTHERMIC Pracs
Posted: 12 Apr 2011, 07:24
I found a couple of new ones to add to our tried and true endothermic and exothermic prac schedule. The ones we have done fgor years only show a small temperature drop
One is really safe with the students.
Make a solution of Citric Acid, I don't bother weighing it out, just make sure it isnt too weak. Pour about 25 mLs of this into a small beaker and add 15g of sodium bicarbonate. It fizzes at first and as it does the temperature reduces quite quickly.
To 32 gms of Barium Hydroxide with 17 gms of ammonium thiocyanate or ammonium chloride and stir around. It becomes an icy slush. It gives off a little ammonia gas so make sure you do it in a well-aired space. Quite dramatic! But teacher only...
One is really safe with the students.
Make a solution of Citric Acid, I don't bother weighing it out, just make sure it isnt too weak. Pour about 25 mLs of this into a small beaker and add 15g of sodium bicarbonate. It fizzes at first and as it does the temperature reduces quite quickly.
To 32 gms of Barium Hydroxide with 17 gms of ammonium thiocyanate or ammonium chloride and stir around. It becomes an icy slush. It gives off a little ammonia gas so make sure you do it in a well-aired space. Quite dramatic! But teacher only...