Ask a Teacher

Search



explain an experiment to prove the high diffussing rate of ammonia?
APPARATUS

Glass tube, Two Corks, Strips of Red Litmus paper, A Clamp and Stand, Cotton Wool, Ammonium Hydroxide solution, Glass Rod


METHOD

Set up the glass tube held horizontally by a clamp and place a cork in one end. Place squares of Red litmus paper of dimension 5 mm × 5 mm at 10 cm intervals along length of the tube, using the glass rod. Soak a  small piece of cotton wool in the ammonium hydroxide solution and place it in the end of the tube. Seal the tube with another cork to prevent the ammonia escaping. and start a stopwatch immediately. now analyse how long the ammonia takes to diffuse past each piece of litmus paper by measuring how long each piece take to turn blue.

ANALYSIS

The red litmus paper turns blue, which shows that the alkaline ammonia molecules have reacted with the litmus paper, proving the ammonia diffused down the tube. The ammonia does this since it moves from an area of high concentration, the cotton wool, to that of low concentration, the rest of the tube, along the concentration gradient. The ammonia is also said to be moving from an area of high partial pressure to that of lower partial pressure. The ammonia molecules simply spread out into the air. The graph is an upward curve, showing that the speed of the diffusion is slowed towards the end of the experiment as the ammonia  diffused further away from its orgin. This happens because the further the ammonia has to go, the fewer molecules there are to diffuse.


comments powered by Disqus