Acids, bases, salts Flashcards
aid in memorization of topics and subtopics
a substance that contains hydrogen which can be replaced directly or indirectly by a metal to form a salt
acid
a proton donor
acid
a substance which form hydronium ions when dissolved in water
acid
how are hydronium ions formed?
when water molecules combine with hydrogen ions released by acids
which two substances have opposite properties and have the ability to neutralise each other?
acids and bases
acids which did not dissolve in water
covalent molecules
they are made up of nonmetals bonded together by sharing electron pairs.
covalent molecules
what happens to acids when added to water?
the acid molecules ionise forming positive hydrogen ions and negative anions
when ______ dissolves in water it donates its hydrogen ions (protons) to the water molecules
acids
what in aqueous solutions of acids gives them their characteristic properties?
positive hydrogen ions (H+ ions)
these solutions are described as being acidic
aqueous solutions
what are the general properties of acids in aqueous solution?
they have a sour taste
they are corrosive
they change blue litmus to red
they have a pH value of less than 7
they conduct an electric current
what happens when an acid reacts
When acids react the hydrogen ( H+ ) ions in the acid are replaced by metal or ammonium ions to form a salt
a reactive metal + acid forms
salt and hydrogen
base + acid forms
salt and water
a metal carbonate + acid forms:
salt, carbon dioxide, water
a metal hydrogencarbonate + acid:
salt, carbon dioxide, water
how are acids classified?
they are classified according to their basicity
basicity
the number of hydrogen (H+) ions produced per molecule of acid when the acid dissolves in water
a substance which will react with an acid to form a salt and water only
base
what is defined as a proton acceptor
a base
monobasic, dibasic and tribasic
acids according to basicity
__________ produce one mole of H+ ions per mole of acid
monobasic acids
___________ produce two mole of H+ ions per mole of acid
dibasic acids
produce three H+ ions per molecule
tribasic acids
what acid can only form normal salts?
monobasic acids
what two types of acids can form both normal salts and acid salts
dibasic and tribasic acids
a compound that reacts with water to form an acid
acid anhydrides
an oxide that either produces an acidic solution upon addition to water, or acts as an acceptor of hydroxide ions
acidic oxides
CO2, SO2, SO3, NO2
acidic oxides of non-metals
which substances do bases include?
metal oxides, metal hydroxides, ammonia
what occurs when a base reacts with acid
the oxygen ions or hydroxide ions in the base accept the hydrogen ions forming water
a base which dissolves in or reacts with water to form a solution that contains OH- ions
an alkali
a solution is described as __________
alkaline
what are the general properties of aqueous solutions in alkalis:
they have a bitter taste
they are corrosive
they feel soapy
they change red litmus to blue
they have a pH value greater than 7
they conduct an electric current
bases react with
acids and ammonium salts
what happens when bases react with ammonium salts
when heated, bases react with ammonium salts to produce a salt, ammonia and water
acids and alkalis are recognized using ___________
indicators
a substance which has one colour when mixed with an acidic solution and another colour when mixed with an alkaline solution
indicators
the common indicators
litmus
methyl orange
screened methyl orange
phenolphthalein
the strength of an acid or alkali depends on
the degree of ionisation; which occur when they dissolve in water
fully ionised when they dissolve in water
strong acids and strong alkalis
their solutions contain a high concentration of H+ ions or OH- ions
strong acid (H+) and strong alkali (OH-)
they are strong electrolytes
strong acids and alkalis
partially ionised when dissolved in water
weak acid and weak alkali
their solutions contain a low concentration of H+ ions or OH- ions
weak acid (H+) and weak alkali (OH-)
they are weak electrolytes
weak acids and weak alkalis
the strength of an acid or alkali is measured on the pH scale using __________
universal indicator
colours of universal indicator
red, orange, yellow, green, blue-green, green, purple
react with both acids and strong alkalis to form a salt and water
amphoteric oxides and amphoteric hydroxides
amphoteric oxide + acid
salt and water
amphoteric hydroxide + acid
salt and water
strong alkali + amphoteric oxide
salt and water
strong alkali + amphoteric hydroxide
salt and water
the oxides and hydroxides of which elements are amphoteric?
aluminium, zinc, lead + more
aluminium oxide
Al2O3
zinc oxide
ZnO
lead (II) oxide
PbO
aluminium hydroxide
Al(OH)3
zinc hydroxide
Zn(OH)2
lead (II) hydroxide
Pb(OH)2
oxides can be classified into four groups:
acidic oxides, basic oxides, amphoteric oxides, neutral oxides
oxides of some non-metals which react with alkalis to form a salt and water
acidic oxides
most acidic oxides also react with water to form an acid, i.e. they are…
acid anhydrides
oxides of metals which react with acids to form a salt and water
basic oxides
name the basic oxides that are also classified as alkalis because they react with water to form a solution containing OH- ions
potassium oxide
sodium oxide
calcium oxide
oxides of some metals which react with both acids and strong alkalis to form a salt and water
amphoteric oxides
list three common amphoteric oxides
aluminium oxide. zinc oxide, lead (II) oxide
oxides of some non-metals which do not react with acids or alkalis
neutral oxides
name some neutral oxides
carbon monoxide, nitrogen monoxide, dinitrogen monoxide
