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Topic 4: The Particulate Nature of Matter - Coggle Diagram
Topic 4: The Particulate Nature of Matter
States of Matter
solid
fixed shape
fixed volume
not compressible
liquid
no fixed shape
fixed volume
not compressible
gas
no fixed shape
no fixed volume
compressible
Kinetic Particle Theory
all matter is made up of tiny particles
particles are in constant and random motion
LIQUID
Arrangement
Closely packed in random arrangement
Forces of Attraction
Strong
Movement of Particles
Free to move within the liquid by sliding over one another
GAS
Arrangement
Far apart and in random arrangement
Forces of Attraction
Negligible
Movement of Particles
Move at high speeds in all directions
Explanation of observations in everyday life using the particulate model of matter
Different states of matter have different densities
density of gas < liquid < solid
for the same substance (same volume), gas has fewer particles than a liquid, which has fewer particles than a solid
Gas exerts a pressure on the container
gas particles - constant random motion
hit the wall of the container & exert a force
SOLID
Arrangement
Very closely packed in regular arrangement
Forces of Attraction
Very strong
Movement of Particles
Vibrate about fixed positions
Changes in State
melting and heating curve
solid
: particles gain energy and vibrate faster (rise in temperature on graph)
melting
: particles overcome forces of attraction between them and move further apart (straight line on graph(no increase/decrease)
liquid:
particles slide over one another(increase in graph)
freezing and cooling curve
liquid
: particles lose kinetic energy and move more slowly(decrease in graph)
freezing
: forces of attraction between particle becomes stronger and particles move closer to each other( no change in graph; constant)
solid: particles vibrate about fixed positions(decrease in graph)
reversible
physical change (no new products formed)
Boiling
change from liquid to gas at a boiling temp( a particular pressure)
fast process
bubbles are observed
occurs throughout the liquid
occurs at a fixed temperature
source of energy needed
evaporation
change from liquid to gas below boiling point
slow process
no visible change
occurs at exposed surface of liquid only
occurs at all termperatures
energy supplied by surroundings
Sublimation
solid to gas without melting
forces of attraction between particles are too weak to remain in liquid
iodine, ammonium chloride, naphthalene, dry ice(solid CO2)
Reverse process: Deposition(gas to solid)
Diffusion
process whereby particles move from a region of higher concentration to a region of lower concentration
Diffusion in gases
A gas jar of air (
colourless
) is inverted on top of a gas jar of bromine vapour (
reddish-brown
). A cover used to separate the gas jars are removed
Observation: Uniform reddish-brown colouration
Explanation:
Air and bromine are made up of tiny particles moving in constant random motion
Bromine particles diffuse into the spaces, vice versa
Diffusion in liquids
a small crystal of potassium manganate (VII) is added to a beaker of distilled water.
Observation: Diffusion slowly takes place until the solution is uniformly purple
How can the rate of diffusion be increased?
use warm water (rate of diffusion increases when temperature increases)
Diffusion in solids
when a piece of copper and nickel are tied together firmly, some copper particles would diffuse into the nickel, vice versa
Process is very slow
particles in solids are held together in
fixed positions
by
strong forces of attraction
Summary
rate of diffusion in gases > liquids > solids
Properties of matter and particles
Matter
may be coloured
Expands when heated as particles move further apart
can feel hot or cold. The temperature of a substance depends on the kinetic energy of its particles (temperature increases when particles gain kinetic energy)
Particles
Are not coloured
Do not get hot or cold
do not expand when heated, they move faster and further apart
Effect of Relative Molecular Mass on Rate of Diffusion
Relative Molecular Mass : Mr
no units, recorded to 1 d.p.
under the same conditions of temp and pressure, a gas with lower Mr diffuse faster than a gas with higher Mr
(Experiment 1) Why does a white ring of solid form closer to the cotton wool soaked in concentrated HCL and further away from aqueous ammonia?
Ammonia has a lower relative molecular mass (17.0) than hydrogen chloride (36.5) and hence diffuses faster, causing ammonium chloride to form further away from aqueous ammonia.
other qns: porous pot
Processes
Condensation (g-l)
Evaporation (l-g)
Melting (s-l)
Sublimation (s-g)
Boiling (l-g)
Deposition (g-s)