Precipitation
Precipitation reactions are a wonderful example of chemical reactions at work. The process of precipitation usually involves the mixing of two clear solutions to produce an insoluble and often coloured solid.
· 0.1M solutions of the following chemicals will be needed.
Sodium carbonate, silver nitrate, lead nitrate, potassium iodide, sodium hydroxide and potassium chromate.
Chemical

Silver nitrate Lead nitrate Copper sulfate Potassium iodide Sodium carbonate Sodium hydroxide Potassium chromate

Silver nitrate
           

Lead nitrate
           
Copper sulfate            
Potassium iodide Yellow precipitate          
Sodium carbonate            
Sodium hydroxide            
Potassium chromate            
Procedure
· Mix the solution as per table in a micro-test tube.
· Observe any solid that may be formed.
· If a precipitation reaction does occur then repeat and video capture the reaction.
· Name the precipitate formed in the appropriate cell and hyperlink it to the image file.
Naming the precipitate
- Take the first name of the first solution and add it to the last name of the second solution.
Eg. When lead nitrate and potassium iodide solutions are mixed. We get the name of the first solution lead and add it to the last name of the second solution iodide.
Placing the names together we come up with the name of the precipitate formed.
Lead iodide.
What is the name of the precipitate formed when silver nitrate solution is mixed with sodium chloride solution? See if you can name all the precipitates in the table above.
If quantities of solutions are scarce then use a black tile and place drops of each solution in a grid as indicated by the table.
If quantities of solutions are scarce then use a black tile and place drops of each solution in a grid as indicated by the table.
A black tile makes it easy to see the colour change.

Home