5.3.2 - Making Insoluble Salts

Question 1

What is a precipitate !?

Answer 1

A precipitate (ppt) is an insoluble solid that forms inside a solution

Question 2

How do precipitates form !?

Answer 2

When the ions in a solution collide with each other, a ppt forms and slowly sinks to the bottom

Question 3

How can you tel if a precipitate will form when mixing two solutions !?

Answer 3

. 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 )

Question 4

How do we make insoluble salts by precipitation !?

Answer 4

. We make insoluble salts by mixing solutions to make a precipitate

( each solution should contain one of the ions needed to make it )

Question 5

What are spectator ions !?

Answer 5

. They are ions which aren’t involved in making the precipitate, they remain in the solution as ‘leftovers’ .

Question 6

What is an ionic equation !?

Answer 6

. A simpler equation for the reaction just involving the ppt

Question 7

Step 1: separating salt from solution (made by precipitation)

Answer 7

. Filter out the salt precipitate
- the residue is the salt we want to keep

(The filtrate is the leftover solution)

Question 8

Step 2: separating salt from solution (made by precipitation)

Answer 8

. Rinse the salt with water

(this washes off traces of the leftover solution)

(Salt doesn’t dissolve as it is insoluble)

Question 9

Step 3 : separating salt from solution (made by precipitation)

Answer 9

. Dry the salt by dabbing it with filter paper

(This removes the last few traces of water, leaving us with a pure dry salt)