C6 Types Of Reaction- Pecipitation, Acid-Base And Redox Flashcards
Indicator
A substance that changes colour with a change in pH
Acid
Proton donor
Strong acid
A proton donor that completely dissociates into ions in water
A weak acid
A proton donor that only partially dissociates into its ions in water
Base
Proton acceptor
Alkali
A soluble base
It can accept protons in solution
Salt
Formed when an acid has one or more of its hydrogen ions replaced by either a metal ion or an ammonium ion
Precipitation reaction
A cation and an anion in a solution combines to from an insoluble substance that precipitates out as a solid
Redox reaction
A reaction when both oxidation and reduction occurs
OIL RIG
Oxidation number
Identifies to number of electrons transferred in a reaction to determine whether a reaction has undergone reduction, oxidation or both
Oxidation rules
All elements in their natural state have the oxidation number zero
Oxidation numbers of the atoms of any molecule add up to 0
Oxidation numbers of the components of any ion add up to the charge of that ion
Calculating oxidation numbers
Rules
- The oxidation numbers of the elements in groups 1, 2 and 13 are always +1, +2 and +3 respectively
- The oxidation number of fluorine is always -1
- The oxidation number of hydrogen is usually +1
- The oxidation number of oxygen is usually -2
- The oxidation number of chlorine is usually -1
Oxidising agent
Encourages oxidation. It is a substance that receives electrons readily
Reducing agent
Encourages reduction. It is a substance that donates electrons readily
Reaction of an acid and a base-neutralisation
Salt + water
Reaction of an acid and an alkali-neutralisation
Salt + water
Reaction of an acid and a carbonate-neutralisation
Salt +water + carbon dioxide
Reaction of an acid and a metal
Salt + hydrogen
Test for carbonate ions
Carbonate + dilute acids = salt + water + carbon dioxide
Bubbles given off/ effervescence
Tests for sulphate ions
Sulphates can be detected by adding a solution of barium chloride.
A white precipitate of BaSO4 is produced
Tests for Halide ions
Halides can be detected by adding a solution of silver nitrate
Precipitates are formed
Ammonia can be added to identify Cl and Br
Cl- White precipitate
Br- cream precipitate
I- yellow precipitate
Tests for ammonium
Can be detected by warming NH4^+ with dilute sodium hydroxide
NH3 is produced which turns moist red litmus paper blue