5.3.2 - Making Insoluble Salts Flashcards
What is a precipitate !?
A precipitate (ppt) is an insoluble solid that forms inside a solution
How do precipitates form !?
When the ions in a solution collide with each other, a ppt forms and slowly sinks to the bottom
How can you tel if a precipitate will form when mixing two solutions !?
. By mixing the ions up and seeing if either of the resulting compounds is insoluble
( if an insoluble compound is formed, it will appear as a precipitate )
How do we make insoluble salts by precipitation !?
. We make insoluble salts by mixing solutions to make a precipitate
( each solution should contain one of the ions needed to make it )
What are spectator ions !?
. They are ions which aren’t involved in making the precipitate, they remain in the solution as ‘leftovers’ .
What is an ionic equation !?
. A simpler equation for the reaction just involving the ppt
Step 1: separating salt from solution (made by precipitation)
. Filter out the salt precipitate
- the residue is the salt we want to keep
(The filtrate is the leftover solution)
Step 2: separating salt from solution (made by precipitation)
. Rinse the salt with water
(this washes off traces of the leftover solution)
(Salt doesn’t dissolve as it is insoluble)
Step 3 : separating salt from solution (made by precipitation)
. Dry the salt by dabbing it with filter paper
(This removes the last few traces of water, leaving us with a pure dry salt)