Unit 5.2 - Classifying Chemical Reactions Flashcards
Thermal Decomposition
substances that only decompose when heated to high temperatures
Combination Reactions
when two reactants combine to form a single product. The general equation can be written as:
X+Y–>XY
Precipitation Reactions
When two clear solutions react to produce an insoluble product known as the precipitate
Ionic Compounds
substances that are made up of a crystal lattice of positive ions (cations) and negative ions (anions)
Features of Ionic Compounds
hard
brittle
can be brightly coloured
always neutral charge
Poly Atomic
poly atomic ions are ions with more than one atom example: NH4 (ammonium)
When written, formula for calcium hydroxide is Ca(OH)2 because two hydroxide ions are needed for every calcium ion.
chemical reaction
a chemical reaction occurs when a new substance is produced
Signs of a Chemical Reaction
colour change gas given off change in temperature solids produced in solution one metal deposited in another
Reaction Types
decomposition combustion precipitation displacement neutralisation metal + acid
Decomposition Reaction
when a single reactant breaks apart to form several products; it is decomposing.
Reaction can be written as
XY–>X+Y
Oxidation Reaction
If substance combines with oxygen during chemical reaction. e.g combustion and corrosion
combustion - substances burn rapidly in oxygen and produce small amounts of heat and light.
gains oxygen, or loses electrons
Reduction Reaction
opposite of oxidisation.
occurs when compound loses oxygen atoms
when copper two oxide is heated to high temp, and mixes with carbon, there is less oxygen and the copper two ion and forms copper and carbon dioxide product
copper oxide is reduced
loses oxygen, or gains electrons
Metal Displacements
simple redox reactions that only involve the transfer of electrons from one metal atom to another
Redox
abbreviation for oxidation and reduction pairs of reactions
