IB CHEMISTRY:
TOPIC 1 QUANTITATIVE CHEMISTRY NOTES
1.1 Introduction to the particulate nature of matter and
chemical change
Nature of Matter
Matter is anything that takes up space
Matter can either refers to the particles (pure substances) or combination of a
substances (mixtures):
Pure Substances
A pure substance has definite and constant composition
For a pure substance, from a particle perspective all particles will look and
remain the same
Definitions
Element – Atoms with same number of protons
Molecule – Two or more elements chemically joined together
Compounds – Two or more different elements chemically joined together
in a fixed ratio
From their definitions: All compounds are molecules, but not all molecules are
compounds
Mixtures
Mixture: A combination of pure substances
Mixtures contain more than one element and/or compound that are not
chemically bonded together, so retain their individual properties
Mixtures can be homogeneous or heterogeneous:
Homogeneous mixtures are the same mixture throughout
They will have a uniform composition e.g. salt water
Heterogeneous mixtures have a different mixture throughout
They will have visibly different substances throughout, a
non-uniform composition e.g. orange juice with pulp
Chemical Equation
Chemical Equation: Describes what happens during a chemical reaction
A chemical reaction will always have reactants and products as well as some
special reaction conditions if required
Reactants are always on the left, and products are always on the right
, Chemical equations usually use state symbols to identify the state of the
products and reactants
State Symbols
Reactants and products can be in one of four states
o (s): solid
o (l): liquid
o (g): gas
o (aq): aqueous solution (dissolved in a solvent)
Types of state changes:
o Solid liquid = Melting, liquid solid = freezing
o Liquid gas = Evaporation/boiling, gas liquid = condensation
o Solid gas = Sublimation, gas solid = deposition
Note, during a state change there will be no increase or decrease in
temperature
Adding temperature only increases the kinetic energy of the molecules, which
will eventually break the bonds, then the molecules will change state
It also takes a higher temperature to turn a solid to a liquid, and an even
greater temperature to turn a liquid to a gas
Physical and Chemical Changes
In a physical change, no new substances are produced
o Example: Melting/boiling is a physical change there is merely a
change of state but no new particles being produced.
In a chemical change, new chemical substances are formed
o The atoms in the reactants are rearranged to form new products
TOPIC 1 QUANTITATIVE CHEMISTRY NOTES
1.1 Introduction to the particulate nature of matter and
chemical change
Nature of Matter
Matter is anything that takes up space
Matter can either refers to the particles (pure substances) or combination of a
substances (mixtures):
Pure Substances
A pure substance has definite and constant composition
For a pure substance, from a particle perspective all particles will look and
remain the same
Definitions
Element – Atoms with same number of protons
Molecule – Two or more elements chemically joined together
Compounds – Two or more different elements chemically joined together
in a fixed ratio
From their definitions: All compounds are molecules, but not all molecules are
compounds
Mixtures
Mixture: A combination of pure substances
Mixtures contain more than one element and/or compound that are not
chemically bonded together, so retain their individual properties
Mixtures can be homogeneous or heterogeneous:
Homogeneous mixtures are the same mixture throughout
They will have a uniform composition e.g. salt water
Heterogeneous mixtures have a different mixture throughout
They will have visibly different substances throughout, a
non-uniform composition e.g. orange juice with pulp
Chemical Equation
Chemical Equation: Describes what happens during a chemical reaction
A chemical reaction will always have reactants and products as well as some
special reaction conditions if required
Reactants are always on the left, and products are always on the right
, Chemical equations usually use state symbols to identify the state of the
products and reactants
State Symbols
Reactants and products can be in one of four states
o (s): solid
o (l): liquid
o (g): gas
o (aq): aqueous solution (dissolved in a solvent)
Types of state changes:
o Solid liquid = Melting, liquid solid = freezing
o Liquid gas = Evaporation/boiling, gas liquid = condensation
o Solid gas = Sublimation, gas solid = deposition
Note, during a state change there will be no increase or decrease in
temperature
Adding temperature only increases the kinetic energy of the molecules, which
will eventually break the bonds, then the molecules will change state
It also takes a higher temperature to turn a solid to a liquid, and an even
greater temperature to turn a liquid to a gas
Physical and Chemical Changes
In a physical change, no new substances are produced
o Example: Melting/boiling is a physical change there is merely a
change of state but no new particles being produced.
In a chemical change, new chemical substances are formed
o The atoms in the reactants are rearranged to form new products
