Complete chemistry revision for Cambridge IGCSE, (9-1) and O/L
Mind map for acid , base and salt
Acids
An acid is an H+ ion (or proton) Bases
Donor in aqueous solutions. A chemical substance that can accept
Hydrogen ions in water as well as if it
Acids are completely or partially ionises Nutralises an acid, are known as bases.
In water.
An alkali is a water soluble base.
Acids feel irritable and burning sensation An alkali is an H+ ion (or proton)
On skin. It damage the skin. acceptor or OH- donor .
The acidity of a solution is expressed All the alkalis are bases but all the
by the concentration of its H+ ions in Acid , base and salt Bases are not alkalis, some bases
the solution . It is known as the Are not soluble in water.
Measuring pH of the solutions. Any chemical substance you choose Bases feel slippery( soapy) on the
from your lab, it may be an acid,
The pH scale shows how acidic Skin.
base (or alkali) or a salt.
or alkaline a solution is.
The pH value of bases are higher than
Acids and alkali ( water soluble bases)
The pH value of acids are lesser than 7.
only show their properties when they
7. are in aqueous solutions. Example for bases
Examples of acids Sodium hydroxide
Sulfuric acid Ammonium hydroxide
Hydrogen carbonate ( carbonic)acid Copper oxide
Nitric acid Calcium oxide
Ethanoic acid
Salts
A salt is a compound formed when some or all the hydrogen ions in an acid are replaced by metal
ions or ammonium ions.
For the formation of salts, the anionic part of acid and cationic part of base is involved.
When an acid and a base get reacted to form salt, the parent acid and the parent base can be
determined by splitting the salt into cationic and anionic parts of the given salt.
Some salts are easily soluble in water and some are not soluble.
The pH value of most of the salts are 7 and few of salts can be slightly acidic or basic( pH is slightly
High or lower than 7)
Examples for salts
Sodium chloride
Ammonium sulphate
Lead bromide
Copper nitrate
, Complete chemistry revision for Cambridge IGCSE, (9-1) and O/L
Mind map for acids
Strengths of acids Properties of acids
The relative strength of an acid *Acid is sour in taste ( do not taste laboratory chemicals !!)
is found by comparing one acid with *They are completely of patially soluble in water
another. *They are corrosive
The strength of any acid depends upon *Acid changes the colour of indicators.
how many molecules dissociate (or ionise) * They are electrolytes
when the acid is dissolved in water. * They give free H+to the aqueous solutions
Strong acids
Strong acids are the acids which completely Identification of acids: Acids can be identified
ionises in water . Using chemical and physical tests
pH range of strong acids are from 0 to 3. Litmus papers -Indicators can be liquids
Acids or even used in a paper form. They become
Example: Acids are H+ or proton different colours with different solutions.
HCl – hydrochoric acid Donors. The most common indicator is litmus.
HNO3 – nitric acid Acids show their acidic Acid changes the colour of blue litmus
H2SO4 - sulfuric acid Properties in aqueous To red.
Solution. PH meter - The pH electrode is placed into
Examples of dissociation of acids in water. If an acid to behave as an H+ the solution and a pH reading is given on
The reaction gives free H+ to the solution. ion donor , there must be an the digital display.
HCl(aq) → H+(aq) + Cl- (aq) another substance Universal indicator-This is a mixture of dyes
present to accept the H+ ion. Neutral colour of the indicator – green
HNO3(aq) → H+(aq) + NO-3(aq) With weak acids – green to orange/ yellow
With strong acid – green to red
H2SO4 (aq) → 2H+(aq) + SO42-(aq) Using a metal carbonate : Metal carbonates
React with acid gives efferevasence of carbon
Weak acids Dioxide gas. Confirm the gas by passing through
Weak acids partially ionises in water . The lime water .
The pH range of weak acids are from 4 to 6.
A weak acid such as ethanoic acid, which is Chemical reactions of acids
found in vinegar, produces few hydrogen 1. With metals
ions when it dissolves in water compared acid + metal→salt + hydrogen
with a strong acid of the same concentration. Mg (s) + H2SO4 (aq) →MgSO4 (aq) + H2(g)
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H 2(g)
It is only partially ionised. Weak acid 2. Metal oxides
is a solution has a higher pH than a acid + metal oxide →salt + water
strong acid, but still less than 7. H2SO4(aq) + K2O(s) → K2SO4(aq)+ H2O(l)
HNO3(aq) + ZnO(s) → Zn(NO3)2 + H2O(l)
Examples: 3. Metal carbonates
Ethanoic acid (CH3COOH) acid + carbonate → salt + water +carbon dioxide
Formic acid (HCOOH) CaCO3 (s) +2HCl(aq) → CaCl2 (aq) + H2O (l) + CO2 ( g)
Hydrogen carbonate acid (H2CO3) CuCO3 (s) + 2HNO3(aq) → Cu(NO3)2(aq) + CO2(g) + H2O(l)
4.Metal hydroxides
Examples of dissociation of weak acids: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
H2CO3 ⇌ H+ + HCO3- NH4OH(aq) + HNO3 → NH4NO3(aq) +H2O(l)
CH3COOH⇌ H+ + CH3COO- Neutralisation reaction: Neutralisation is a reaction with acid that gives water and
Basicity of acids: The number of hydrogen Salt. An acid-alkali neutralisation is hydrogen ions (H+) from the acid react with
Atoms in acids are known as basicity. The hydroxide ions (OH–) from the alkali to form water.
Basicity of HCl is 1. The basicity of H2SO4 is Reaction with amphoteric oxide: metal reacts with amphoteric oxide to form salt
2. Water.
Mind map for acid , base and salt
Acids
An acid is an H+ ion (or proton) Bases
Donor in aqueous solutions. A chemical substance that can accept
Hydrogen ions in water as well as if it
Acids are completely or partially ionises Nutralises an acid, are known as bases.
In water.
An alkali is a water soluble base.
Acids feel irritable and burning sensation An alkali is an H+ ion (or proton)
On skin. It damage the skin. acceptor or OH- donor .
The acidity of a solution is expressed All the alkalis are bases but all the
by the concentration of its H+ ions in Acid , base and salt Bases are not alkalis, some bases
the solution . It is known as the Are not soluble in water.
Measuring pH of the solutions. Any chemical substance you choose Bases feel slippery( soapy) on the
from your lab, it may be an acid,
The pH scale shows how acidic Skin.
base (or alkali) or a salt.
or alkaline a solution is.
The pH value of bases are higher than
Acids and alkali ( water soluble bases)
The pH value of acids are lesser than 7.
only show their properties when they
7. are in aqueous solutions. Example for bases
Examples of acids Sodium hydroxide
Sulfuric acid Ammonium hydroxide
Hydrogen carbonate ( carbonic)acid Copper oxide
Nitric acid Calcium oxide
Ethanoic acid
Salts
A salt is a compound formed when some or all the hydrogen ions in an acid are replaced by metal
ions or ammonium ions.
For the formation of salts, the anionic part of acid and cationic part of base is involved.
When an acid and a base get reacted to form salt, the parent acid and the parent base can be
determined by splitting the salt into cationic and anionic parts of the given salt.
Some salts are easily soluble in water and some are not soluble.
The pH value of most of the salts are 7 and few of salts can be slightly acidic or basic( pH is slightly
High or lower than 7)
Examples for salts
Sodium chloride
Ammonium sulphate
Lead bromide
Copper nitrate
, Complete chemistry revision for Cambridge IGCSE, (9-1) and O/L
Mind map for acids
Strengths of acids Properties of acids
The relative strength of an acid *Acid is sour in taste ( do not taste laboratory chemicals !!)
is found by comparing one acid with *They are completely of patially soluble in water
another. *They are corrosive
The strength of any acid depends upon *Acid changes the colour of indicators.
how many molecules dissociate (or ionise) * They are electrolytes
when the acid is dissolved in water. * They give free H+to the aqueous solutions
Strong acids
Strong acids are the acids which completely Identification of acids: Acids can be identified
ionises in water . Using chemical and physical tests
pH range of strong acids are from 0 to 3. Litmus papers -Indicators can be liquids
Acids or even used in a paper form. They become
Example: Acids are H+ or proton different colours with different solutions.
HCl – hydrochoric acid Donors. The most common indicator is litmus.
HNO3 – nitric acid Acids show their acidic Acid changes the colour of blue litmus
H2SO4 - sulfuric acid Properties in aqueous To red.
Solution. PH meter - The pH electrode is placed into
Examples of dissociation of acids in water. If an acid to behave as an H+ the solution and a pH reading is given on
The reaction gives free H+ to the solution. ion donor , there must be an the digital display.
HCl(aq) → H+(aq) + Cl- (aq) another substance Universal indicator-This is a mixture of dyes
present to accept the H+ ion. Neutral colour of the indicator – green
HNO3(aq) → H+(aq) + NO-3(aq) With weak acids – green to orange/ yellow
With strong acid – green to red
H2SO4 (aq) → 2H+(aq) + SO42-(aq) Using a metal carbonate : Metal carbonates
React with acid gives efferevasence of carbon
Weak acids Dioxide gas. Confirm the gas by passing through
Weak acids partially ionises in water . The lime water .
The pH range of weak acids are from 4 to 6.
A weak acid such as ethanoic acid, which is Chemical reactions of acids
found in vinegar, produces few hydrogen 1. With metals
ions when it dissolves in water compared acid + metal→salt + hydrogen
with a strong acid of the same concentration. Mg (s) + H2SO4 (aq) →MgSO4 (aq) + H2(g)
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H 2(g)
It is only partially ionised. Weak acid 2. Metal oxides
is a solution has a higher pH than a acid + metal oxide →salt + water
strong acid, but still less than 7. H2SO4(aq) + K2O(s) → K2SO4(aq)+ H2O(l)
HNO3(aq) + ZnO(s) → Zn(NO3)2 + H2O(l)
Examples: 3. Metal carbonates
Ethanoic acid (CH3COOH) acid + carbonate → salt + water +carbon dioxide
Formic acid (HCOOH) CaCO3 (s) +2HCl(aq) → CaCl2 (aq) + H2O (l) + CO2 ( g)
Hydrogen carbonate acid (H2CO3) CuCO3 (s) + 2HNO3(aq) → Cu(NO3)2(aq) + CO2(g) + H2O(l)
4.Metal hydroxides
Examples of dissociation of weak acids: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
H2CO3 ⇌ H+ + HCO3- NH4OH(aq) + HNO3 → NH4NO3(aq) +H2O(l)
CH3COOH⇌ H+ + CH3COO- Neutralisation reaction: Neutralisation is a reaction with acid that gives water and
Basicity of acids: The number of hydrogen Salt. An acid-alkali neutralisation is hydrogen ions (H+) from the acid react with
Atoms in acids are known as basicity. The hydroxide ions (OH–) from the alkali to form water.
Basicity of HCl is 1. The basicity of H2SO4 is Reaction with amphoteric oxide: metal reacts with amphoteric oxide to form salt
2. Water.
