"Chemistry: States of Matter Cheat Sheet"

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Chemistry: States of Matter Revision
• Matter is the scientific word used to describe all of the different
substances and materials found on the Earth. We call solid, liquid
and gas the three states of matter.
Property
Solid
Liquid
Gas
Shape
Shape stays the
Takes the shape
Change shape to
same (fixed)
of the container
fill any space
Volume (amount) Volume stays the
Volume stays the
Volume changes
same
same
(gas can spread
out)
Can it flow?
No
Yes
Yes
Can you
No
No
Yes
compress it?
Density
Have high
Less dense than
Very low
densities
solids
densities.
(generally)
Changing states
• Most substances can exist in all three states (e.g. water can be ice
(solid), liquid or gas (water vapour).
• The state of a substance depends on the temperature.
• Changes of state are brought about by changes in temperature.
Increasing thermal energy (temperature increases)
Solid
(melting)
Liquid
(evaporating)
gas
Decreasing thermal energy (temperature decreases)
Solid
(freezing)
Liquid
(condensation) gas
Note: some substances (e.g. Carbon dioxide) can change straight from a
solid to a gas – this is called sublimation.
Melting point: the temperature at which all solid changes to a liquid.
o
(e.g. water = 0
C)
Boiling point: the temperature at which all liquid changes to a gas
o
(e.g. water = 100
C)
Chemistry: States of Matter Revision
• Matter is the scientific word used to describe all of the different
substances and materials found on the Earth. We call solid, liquid
and gas the three states of matter.
Property
Solid
Liquid
Gas
Shape
Shape stays the
Takes the shape
Change shape to
same (fixed)
of the container
fill any space
Volume (amount) Volume stays the
Volume stays the
Volume changes
same
same
(gas can spread
out)
Can it flow?
No
Yes
Yes
Can you
No
No
Yes
compress it?
Density
Have high
Less dense than
Very low
densities
solids
densities.
(generally)
Changing states
• Most substances can exist in all three states (e.g. water can be ice
(solid), liquid or gas (water vapour).
• The state of a substance depends on the temperature.
• Changes of state are brought about by changes in temperature.
Increasing thermal energy (temperature increases)
Solid
(melting)
Liquid
(evaporating)
gas
Decreasing thermal energy (temperature decreases)
Solid
(freezing)
Liquid
(condensation) gas
Note: some substances (e.g. Carbon dioxide) can change straight from a
solid to a gas – this is called sublimation.
Melting point: the temperature at which all solid changes to a liquid.
o
(e.g. water = 0
C)
Boiling point: the temperature at which all liquid changes to a gas
o
(e.g. water = 100
C)
Particle theory
• All solids, liquids and gases are made of very small particles.
• Particles are always moving.
• Particles are held together by forces (bonds)
State
Forces
How freely can
How far
Model
between
particles move?
apart are the
diagram
particles
particles?
Solid
Strong
Do not move from
Very close –
OOOOOO
place to place:
fixed position.
OOOOOO
vibrate
OOOOOO
Liquid
Weak
Freely – can roll
Fairly close
O O O O
over each other
OOO O OO
OO O O OO
Gas
Very weak
Very freely – move
Very far
O
quickly
apart.
O
O
Using particle theory to explain:
Expansion (getting bigger on heating): Particles gain thermal energy
when heated. This makes the particles move more – making the particles
move further apart from each other – the substance expands.
Compressing (squashing): Solids and liquids do not compress because
there is no space between the particles. You can compress (squash) a gas
because there is lots of space between the particles, so they can be
pushed together.
Density (how heavy something is for its size): Very dense materials (like
metals) have lots of particles paced together into a small space (volume).
Density: the density of a substance tells us how much of a substance is
packed into a certain volume. To calculate density of an object you need
3
to know: mass (g) and the volume (cm
)
Density = Mass
volume
3
Units for density are g/cm
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