Chemical reaction Flashcards
\define oxidation (in terms of electrons)
Oxidation is the loss of electrons
define reduction (in terms of electrons)
reduction is the gain of
electrons
Mg —-> Mg2+ + 2e-
Describe what has happened
Magnesium, loses two electrons to form the Magnesium ion (mg2+ ion)
The magnesium atom has been oxidised as it has lost electrons
This is a oxidation reaction because the magnesium atom has lost electrons
S + 2e- —> S2-
Describe what has happened
Sulfur has gained two electrons and formed the sulfide ion
The sulfur atom has been reduced as it has gained electrons
This is a reduction reaction has the sulfur atom has gained electrons
OIL RIG
Oxidation is loss of electrons
Reduction is gain of electrons
Identify in the reaction below which element (species) has been oxidised and which has been reduced
zinc + copper sulfate –> zinc sulfate + copper
Zn + CuSO4 –> ZnSO4 + Cu
The zinc atom has been oxidised as it has lost two electrons (oxidation is loss of electrons)
The copper ion has been reduced as it has gained two electrons (reduction is gain of electrons)
(We start with the zinc atom, Zn and we end up with the Zinc ion , Zn2+
In order for this to happen, the zinc atom must have lost two electrons, therefore the zinc atom has been oxidised.
We start with the copper ion, Cu2+ and end up with the copper atom, Cu. In order for this to happen, the copper must have gained two electrons, therefore it has been reduced.
zinc + copper sulfate –> zinc sulfate + copper
Zn + CuSO4 –> ZnSO4 + Cu
what type of reaction is this
a displacement reaction
- write ionic equations for displacement reactions
Zn + CuSO4 –> ZnSO4 + Cu
Zn + Cu2+ + SO42- —> Zn2+ A-SO42- + Cu
Zn + Cu2+ —–> Zn2+ + Cu
aq meaning
aq = aqueous solution - dissolved in water
What do acids produce in aqueous solutions
In aqueous solutions, acids produce hydrogen ions (H+ ions)
Write an equation to show how hydrochloric acid ionises in water
(showing hydrochloric acid in aqueous solution)
HCl (aq) –> H+(aq) + Cl- (aq)
Describe what has happened
HCl (aq) –> H+(aq) + Cl- (aq)
This is how hydrochloric acid ionises in water
The molecule has split and released H+ (hydrogen ion)
The chloride ion (Cl-) has also been made (produced)
Write an equation to show how sulphuric acid ionises in water
(showing sulfuric acid in aqueous solution)
And describe what has happened
H2SO4(aq) –> 2H+(aq) + SO42-(aq)
This is how sulfuric acid ionises in water
The molecule has split and released H+ (hydrogen ion)
The sulfate ion (SO42-) has also been made (produced)
Write an equation to show how nitric acid ionises in water
(showing nitric acid in aqueous solution)
And describe what has happened
HNO3(aq) —> H+(aq) NO3-(aq)
This is how nitric acid ionises in water
The molecule has split and released H+ (hydrogen ion)
The nitrate ion (NO3-) has also been made (produced)
What is an acid
A substance that releases H+ ions when in a solution
What is a base
Chemicals which can neutralise acids producing a salt and water
Examples of bases
Metal oxides
Metal hydroxides
Examples of bases
Copper oxide
Iron (III) hydroxide
Sodium hydroxide
Explain why Copper oxide
Iron (III) hydroxide and Sodium hydroxide are bases (are called bases)
All of these are bases because they can neutralise acids producing a salt and water
What is an alkali
Bases which are soluble in water are called alkalis
Out of Copper oxide
Iron (III) hydroxide
Sodium hydroxide
which ones are bases only and which ones are a base and an alkali.
Explain your choices
Copper oxide and Iron (III) hydroxide are both insoluble in water, so these are bases only
Sodium Hydroxide is soluble in water, so sodium hydroxide is both a base and an alkali
What do alkalis produce in aqueous solutions
In aqueous solutions, alkalis produce hydroxide ions (OH- ions) –
- (alkalis are substances that release OH- ions when added to water)
Write an equation to show how sodium hydroxide ionises in water
(showing sodium hydroxide in aqueous solution)
And describe what has happened
NaOH(aq) –> Na+ (aq) + OH- (aq)
The sodium hydroxide is splitting, producing the sodium ion Na+ and the hydroxide ion OH-
The molecule has split and released OH- (hydroxide ion)
The Na+ (sodium ion) has also been made (produced)
What is the pH scale
The pH scale, from 0 to 14, is a measure of the acidity or alkalinity
of a solution,