2 Making Salts Flashcards
In the precipitation method, Two salts are added to make an insoluble salt.
What must be done to the two salts which are added together?
The two soluble salts must be dissolved in water so that their ions are dissociated (in solution)
In the precipitation method, Two soluble salts are added together to form an insoluble salt.
Which two salts can be used to make copper carbonate?
copper nitrate AND sodium carbonate
In the titration method we must titrate until we acheve concordant results. What does this mean?
At least two titres which are within 0.2 cm3 of each other.
In the precipitation method, Two soluble salts are added together to form an insoluble salt.
Which two salts can be used to make barium sulfate?
Barium nitrate AND sodium sulfate
What is the chemical formula and valency of a carbonate ion?
CO32-
In the titration method we must titrate until we acheve concordant results. What is the significance of the mean of the concordant results?
This is the exact volume of acid/alkali needed to neutralise and form a pure salt solution.
Pure crystals of the salt can then be formed from this solution
In the precipitation method, Two soluble salts are added together to form an insoluble salt.
Which two salts can be used to make calcium sulfate?
calcium nitrate AND sodium sulfate
Which of the following salts are soluble?
Na2O
KOH
(NH4)2CO3
All of them!
All oxides, hydroxide and carbonate salts are INSOLUBLE except for sodium, potassium and ammonium salts.
In the titration method we must titrate until we acheve concordant results. What do we do with these concordant results?
We find the mean of the concordant results.

In the titration method we must titrate until we acheve concordant results. Why do we use both a burette and pipette during titration?
Both a pipette and burette allow us to read volumes of solution to a small uncertainty. Making our reading accurate.
Which of the following salts are soluble?
BaSO4
CaSO4
PbSO4
None of them!
All sulphates salts are soluble except for Barium (Ba2+), calcium (Ca2+) or lead (Pb2+)
In the insoluble base method a base is added to a hot acid. What is kept to make the pure sample of the salt?
filtrate OR residue

filtrate
The residue is the excess base added
What is the chemical formula and valency of a iron ion?
Fe2+ OR Fe3+
What is the chemical formula and valency of a silver ion?
Ag1+
What is the solubility rules for halide salts?
Cl-, Br- and I-
All halide salts are SOLUBLE - except for silver (Ag+) and lead (Pb2+)
What is the chemical formula and valency of a lead ion?
Pb2+
What soluble salts could be used to make lead iodide by the precipitation method
lead nitrate
sodium iodide
HINT: You can always choose a nitrate and sodium salt as all nitrate salts are soluble and all sodium salts are soluble
lead nitrate + sodium iodide ⇒ lead iodide + sodium nitrate
In the precipitation method, Two soluble salts are added together to form an insoluble salt.
Which two soluble salts could be used to make lead iodide?
Lead nitrate AND sodium iodide

What are the two questions which you need to answer when determining which method is needed to make a salt?

- Is the salt soluble or insoluble?
- Is it a sodium, potassium or ammonium salt?
Add state symbols to the chemical equation below
Lead nitrate + sodium sulfate ⇒ lead sulfate + sodium nitrate
Pb(NO3)2 + Na2SO4 ⇒ PbSO4 + 2NaNO3
Pb(NO3)2 (aq)+ Na2SO4 (aq) ⇒ PbSO4 (s) + 2NaNO3 (aq)
PbSO4 is the precipitate
In the insoluble base method a base is added to a hot acid. Why must the hot acid be stirred each time the base is added?

The ensure a complete reaction between the base and acid
In the precipitation method, How is the pure salt obtained from the products?
The insoluble pure salt is filtered out as the residue
This residue must be wased with distilled water and allowed to dry.

In the precipitation method, two soluble salts are added together. Why must you stir after they are added together?
The ensure that the reaction is complete

What is the chemical formula and valency of a zinc ion?
Zn2+
Which of the following salts are soluble?
PbCl2
AgBr
PbI2
None of them!
All halides are soluble except for lead (Pb2+) and silver (Ag+) halides!
What is the chemical formula and valency of an ammonium ion?
<span>NH</span>41+
In the insoluble base method a base is added to a hot acid. How are pure crystals of salt produced from the filtrate?

- The filtrate is heated to half volume in an evaporation basin
- Allowed to cool and crystals form
- Filter our crystals and allow to dry

In the titration method we must titrate until we acheve concordant results. How do you know when the acid and alkali have exactly neutralised?
An indicator is used, a colour change indicates that neutralisation has been reached- there are equal H+ and OH- ions.

Which of the following salts are soluble?
Pb(NO3)2
Ca(NO3)2
CuNO3
All of them!
All nitrate (NO31-) salts are soluble
What are the rules for writing ionic equations?

- Dissociate or break apart any substance into its ions which is aqueous (aq)
- Leave any substance which is liquid (l), solid (s) or gas (g) - do not break them apart into ions (They do not form ions)
- Cross out any ions which are the same on both sides of the reaciton - These are called spectator ions!
- Rewrite the equation without the spectator ions
To determine which method to use when making a salt you should answer the following questions
- Is the salt soluble?
YES - ask yourself question 2 NO - U_se precipitation method_
2. Is the salt a sodium, potassium or ammonium salt?
YES - Use titration method NO - Use insoluble base method
Use this to determine how to make potassium sulfate
potassium sulfate
- Is the salt soluble? YES- all sulfates are soluble except for Ba, Ca and Pb
YES - ask yourself question 2 NO - Use precipitation method
- Is the salt a sodium, potassium or ammonium salt? YES= potassium salt!
YES - Use titration method NO - Use insoluble base method
What is the solubility rules for hydroxide salts?
OH-
All hydroxide (OH-) salts are INSOLUBLE - except for sodium (Na+), potassium (K+) or ammonium (NH41+)
In which salt preparation method do we add an acid to an alkali?
ACID + ALKALI
Titration method
What is the solubility rules for sulfate salts?
SO42-
All sulfate salts are SOLUBLE - except for calcium (Ca2+), barium (Ba2+) and lead (Pb2+)
What is the formula for ammonium carbonate?
NH4+ CO32-
Cross and drop valencies
(NH4)2CO3
Which two types of salts are ALWAYS SOLUBLE
All nitrate salts (NO31-) are soluble
All sodium, potassium and ammonium salts are soluble
(Na+, K+ and NH41+)
In which salt preparation method do we add a base to an acid?
ACID + BASE
Insoluble base method
To determine which method to use when making a salt you should answer the following questions
- Is the salt soluble?
YES - ask yourself question 2 NO - U_se precipitation method_
2. Is the salt a sodium, potassium or ammonium salt?
YES - Use titration method NO - Use insoluble base method
Use this to determine how to make Lead iodide
Lead iodide
- Is the salt soluble - No - all halides are soluble except for silver and lead
YES - ask yourself question 2 NO - Use precipitation method
What is the chemical formula and valency of a copper ion?
Cu2+ OR Cu1+
In which salt preparation method do we add a salt to a salt?
SALT + SALT
Precipitation method
Two soluble salts are added together to form an insoluble salt
In the insoluble base method a base is added to a hot acid. How do you know that all the acid has reacted and a pure solution of salt has been acheived?

When some base is left in the bottom of the beaker which will not disappear (not react)
What is the solubility rules for carbonate salts?
CO32-
All carbonate (CO32-) salts are INSOLUBLE - except for sodium (Na+), potassium (K+) or ammonium (NH41+)
In the titration method we must titrate until we acheve concordant results. Why do then repeat the titration without an indicator?
To make a pure sample of the salt without indicator
To determine which method to use when making a salt you should answer the following questions
- Is the salt soluble?
YES - ask yourself question 2 NO - U_se precipitation method_
2. Is the salt a sodium, potassium or ammonium salt?
YES - Use titration method NO - Use insoluble base method
Use this to determine how to make copper sulfate
Copper sulfate
- Is the salt soluble?- YES - All sulphates are soluble except for Ca, Ba and Pb
YES - ask yourself question 2 NO - Use precipitation method
- Is the salt a sodium, potassium or ammonium salt? NO
YES - Use titration method NO - Use insoluble base method
What is the chemical formula and valency of a sulfate ion?
SO42-
In the titration method we must titrate until we acheve concordant results. These volumes are averaged and then this volume of acid/alkali are added without an indicator. This solution is now a pure salt solution. How are the pure crystals obtained from this solution?
- The salt solution is heated to half volume in an evaporating dish
- The solution is cooled and crystals form
- These crystals are filtered out and allowed to dry
In the insoluble base method, why must the base be added in excess?

To ensure that all the acid has reacted leaving a pure salt solution and excess solid base which can be removed by filtering
In the insoluble base method, why must the acid be heated?

To speed up the rate of reaction between the base and acid.
What is the chemical formula and valency of a nitrate ion?
NO31-
Which of the following salts are soluble?
NaBr
KNO3
NH4CO3
They are all soluble - All Na+, K+ and NH4+salts are soluble
NaBr
KNO3
NH4CO3
What is the solubility rules for oxide salts?
All oxide (O2-)salts are INSOLUBLE - except for sodium (Na+), potassium (K+) or ammonium (NH41+)