salts and ionic equations Flashcards
A salt is…
A salt is a substance formed when a metallic ion/an ammonium ion (NH4+) replaces one or more hydrogen ions of an acid.
What groups of substances are all soluble in water?
- All Group I (sodium, potassium), ammonium salts (acronym: SPA)
- All nitrates
What groups of substances are soluble with exceptions?
All sulfates are soluble except lead (II), silver, barium, calcium
(barium and calcium sparingly soluble)
Chlorides, iodides, bromides - all except lead (II) and silver
What groups of substances are entirely insoluble?
- All carbonates, metal oxides, hydroxides are insoluble (except Group I carbonates/oxides/hydroxides and ammonium carbonates) (acronym: CMI or CMM or CMIM)
- Note that oxides of Group II elements (Ca, Sr and Ba) increase in solubility from calcium down.
Precipitation is… (and is precipitation used to prepare insoluble or soluble salts?)
Precipitation is a reaction involving mixing two aqueous solutions to form an insoluble solid that separates out from the reaction mixture. The insoluble solid is the precipitate. Precipitation is used in the preparation of insoluble salts.
Procedure of precipitation: 2 solutions are selected. One of the reagents contributes the ___, while another contributes the ___.
Procedure of precipitation: 2 solutions are selected. One of the reagents contributes the cation, while another contributes the anion.
Procedure of precipitation: One of the reagents will be added in ___ while the other would be left as the ___ reagent.
Procedure of precipitation: One of the reagents will be added in excess while the other would be left as the unreacted reagent.
Procedure of precipitation: The insoluble salt is formed as a ____ and can then be separated from the aqueous solution by ____.
Procedure of precipitation: The insoluble salt is formed as a precipitate and can then be separated from the aqueous solution by filtration.
Procedure of precipitation: The salt is washed with ____ ___ and wiped dry with ___ ___ to remove contaminant ____ that are on the ____ of the crystals.
Procedure of precipitation: The salt is washed with distilled water and wiped dry with filter paper to remove contaminant chemicals that are on the surface of the crystals.
What are the methods of preparation for soluble salts?
Reaction of acid with an insoluble substance (solid-acid reaction) (ISTA), titration
What are the 3 possible reactions for solid-acid reaction?
Acid + REACTIVE (but should NOT be used with highly reactive eg group I metals) metal (has to be added in excess) –> salt + hydrogen
Acid + insoluble base –> salt + water
Acid + insoluble metal carbonate –> salt + water + CO2
Why are insoluble reactant (carbonate/base/metals) added in excess before being warmed?
To ensure that the reaction is complete and that all the soluble reactant is used up.
Procedure of solid-acid reaction: The resultant mixture can then be ____ to remove excess, unreacted ___. The ____ is the solution of the soluble salt.
Procedure of solid-acid reaction: The resultant mixture can then be filtered to remove excess, unreacted solids. The filtrate is the solution of the soluble salt.
Procedure of solid-acid reaction: Heat the ___ gently until it is _____. Allow the _____ solution to cool for ____ to form.
Procedure of solid-acid reaction: Heat the filtrate gently until it is saturated. Allow the saturated solution to cool for crystals to form.
Procedure of solid-acid reaction: ___ the mixture to collect the crystals. Wash the soluble salt crystals with a small amount of __ ____ ___. Dry the crystals between pieces of ___ ___.
Procedure of solid-acid reaction: Filter the mixture to collect the crystals. Wash the soluble salt crystals with a small amount of cold distilled water. Dry the crystals between pieces of filter paper.
