Chemical changed and Interactions Flashcards
Chemical change
- involves the rearrangement of atoms
- new substance is formed
- properties of substance is different
- irreversible
EXAMPLES
- decomposition
- oxidation
- combustion
- combination
- neutralisatino
Physical change
- does not involve a rearrangement of atoms
- no new substance is formed
- properties are same
- reversible
EXAMPLES
- melting
- freezing
- evaporations
- boiling
- condensation
- sublimation
Decomposition
a compound is broken down into two or more simpler substances by heat or electricty
Thermal decomposition
- a compound is broken down into two or more simpler substances with the effect of heat
EXAMPLE
- thermal
decomposition of carbonates
- thermal decomposition of sugar
Electrolysis
- a compound is broken down into two or more simpler substances with the effect of electricity
EXAMPLES
- electrolysis of molten sodium chloride
-
Combination
a process in which two or more substances combine to form a single product
Oxidisation
a process in which a substance gains oxygen
EXAMPLE
- corrosion of metal
- aerobic respiration in which it releases energy by breaking down glucose in the presence of oxygen to form co2 , water and cellular energy
Reduction
a process in which a substance loses oxygen
Combustion
is a process in which a substance reacts with o2 to release heat
- complete combustion occurs when there is abundance of o2
- fuel + oxygen = water + co2
- incomplete combustion occurs when there is a limited supply of oxygen
- fuel + o2 = carbon momoxide + water
Neutralisation
a process in which alkali and acid react to form salt and water only
Law of coservation of mass
states that mass is not gained or lost in a chemical reaction. hence the total mass of the products must be equal to the total mass of the reactants.
- the number of atoms of each element must be same before and after chemical reaction
symbols
acid, alkali = aq
water = l
comman gases = g
all metals except mercury
