lectures for students in GCSE .explaining particles and purification method.It explains Matter, state of matter,changing state,diffusion ,brownian motion,appartus used in chemistry and their use

1. CHEMISTRY
IGCSE
Mrs Anum toqueer waqas
Msc chemistry

2. 1.PARTICLES AND
PURIFICATION
PART 1
1.1 SOLIDS, LIQUID, GASES
1.2 DIFFUSION
1.3 APPARATUS FOR
MEASURING
PART 2
1.4 PAPER CHROMATOGRAPHY
1.5 PURITY OF SUBSTANCE
1.6 METHOD OF PURIFICATION

3. • MATTER
ALL MATTER IS MADE UP OF PARTICLES .THREE TYPES
OF PARTICLES MAKE UP THE MOST MATTER
• ATOM IT IS THE SMALLEST PARTICLES THAT CANNOT BE BROWKEN DOWN BY CHEMICAL MEANS.
• MOLECULES IT IS PARTICLE OF TWO OR MORE ATOMS JOINED TOGETHER.
• ION IT IS AN ATOM OR GROUP OF ATOMS THAT CARRIES AN ELECTRICAL CHARGE.
• THE KINETIC PARTICLE THEORY OF MATTER IS A MODEL THAT DESCRIBES THE ARRANGEMENT,
MOVEMENT AND ENERGY OF PARTICLES IN A SUBSTANCE. THE MODEL IS USED TO EXPLAIN THE
PHYSICAL PROPERTIES OF SOLIDS, LIQUIDS AND GASES.
Core content

4. 1.1 SOLIDS,LIQUID AND GASES
THERE ARE THREE STATES OF MATTER
SOLID; A solids has a definite shape and volume
but cannot flow.
LIQUID; A liquid has a definite volume but takes
the shape of its container .It can flow
GASES A gas has no definite
volume it can spread every where throughout
its container.

5. WE CAN EXPLAIN, THE PROPERTIES OF SOLID
,LIQUID AND GASES BY LOOKING AT THEIR
PARTICLES,ARRANGEMENT,MOVEMENT AND
PROXIMITY
Arrangement:fixed
Movement:vibrational only
Proximity:close together
Arrangement:random,
Movement:slide past each
other
Proximity:close together
Arrangement:random
Movement:move
everywhere rapidly
Proximity:far apart

6. CHANGING STATE
Explaining change of state
Melting, evaporating and boiling
Energy must be transferred, by heating, to a substance for
these changes of state to happen. During these changes
the particles gain energy, which is used to break or
overcome:
1. some of the bonds between particles during melting
2. all the remaining bonds between particles during
evaporating or boiling
Evaporation can take place below the boiling point of a
substance. This is why damp clothes dry when they are
hung from a washing line. Boiling happens at the boiling
point, when the rate of evaporation is at its maximum.
Condensing and freezing
Energy must be transferred from a substance to the
environment for condensation and freezing to happen.
During these changes of state, the particles lose energy as
bonds form between the particles.

7. CHANGING STATE
Some substances can change directly from solid to gas, or
from gas to solid, without becoming a liquid in between.
This is called sublimation. Solid carbon dioxide ('dry ice')
and iodine can sublime.
Comparison Predicted state
Given temperature < melting point Solid
Given temperature is between melting
and boiling points Liquid
Given temperature > boiling point Gas
Question
The melting point of oxygen is -218°C and its boiling point
is -183°C. Predict the state of oxygen at -200°C.
Oxygen will be in the liquid state at -200°C (because this is
between its melting and boiling points).

8. A HEATING CURVE OF SYALICYLIC ACID
• A SOLID CALLED SALICYLIC ACID IS HEATED AT A
CONSTANT RATE.WE CAN RECORD ITS TEMPRATURE
AT INTERVALS.A GRAPH OF TEMPRATURE AGAINST
TIME SHOWS THAT THE TEMPRATURE DOES NOT
INCREASE STEADILY ALL THE WAY
• IN THE HEATING CURVE ,THE HORIZONTAL PART OF
THE GRAPH IS WHERE THE SOLID IS CHANGING TO
LIQUID.THIS IS ITS MELTING POINT.

9. 1.2 DIFFUSION
WHAT IS DIFFUSION
• THE RANDOM MOVEMENT OF DIFFERENT PARTICLES
SO TYHEY GET MIXED UP IS CALLED
DIFFUSION.DIFFUSION RESULTS IN THE PARTICLES
SPREADING THROUGHOUT THE SPACE
AVAILABLE.THE OVERALL DIRECTION OF THE
MOVEMENT IS FROM WHERE THE PARTICLES ARE
CONCENTRATED TO WHERE THEY ARE LESS
CONCENTRATED HOW EVER THE PARTICLES ARE
MOVING RANDOMLY SO SOME ARE MOVING FROM
LESS CONCENTATED TO MORE CONCENTRATED
AREA.

10. EXAMPLES OF DIFFUSION
DIFFUSION OF INK
SPEED OF DIFFUSION AND
MOLECULAR MASS
FORMATION OF AMMONIUM
CHLORIDE

11. DESCRIBE AND EXPLAN DEPENDENCE OF RATE OF
DIFFUSSION ON MOLECULAR MASS
• GASES DONT DIFFUSE AT THE SAME RATE EVERY TIME. IT DEPENDS ON THESE TWO FACTORS:
1. THE MASS OF THE PARTICLES
THE LOWER THE MASS OF THE GAS PARTICLES, THE FASTER IT WILL DIFFUSE BECAUSE THE LIGHTER PARTICLES
WILL BOUNCE FURTHER THAN THE HEAVIER ONES AFTER IT COLLIDES WITH OTHER PARTICLES. SO WE CAN SAY
THAT THE LOWER ITS RELATIVE MOLECULAR MASS, THE FASTER A GAS WILL DIFFUSE.
2. THE TEMPERATURE
WHEN A GAS IS HEATED, ITS PARTICLES TAKE IN HEAT ENERGY WHICH MAKES THEM MOVE FASTER. THEY WILL
BE ABLE TO COLLIDE WITH MORE ENERGY AND BOUNCE FURTHER AWAY. THIS MAKES THE GAS DIFFUSE FASTER.
SO WE CAN SAY THAT THE HIGHER THE TEMPERATURE, THE FASTER A GAS WILL DIFFUSE.

12. BROWNIAN MOTION
• EVIDENCE FOR THE MOVEMENT OF PARTICLES CAME TO LIGHT
IN 1827 WHEN THE BOTANIST,ROBERT BROWN OBSERVED
THAT FINE POLLON GRAINS ON THE SURFACE OF WATER WERE
NOT STATIONARY.
• IT WAS 96 YEARS LATER,IN 1923 THAT SCIENTIST CALLED
NORBET WIENER EXPLAINED WHAT BROWN OBSERVED.HE SAID
THAT THE POLLEN GRAIN WAS MOVING BECAUSE THE MUCH
SMALLER AND FASTER MOVING WATER PARTICLES WERE
CONSANTLY COLLIDING WITH THEM.
• THIS RANDOM MOTION OF VISIBLE PARTICLE (POLLEN GRAIN)
CAUSED BY MUCH SMALLER,INVISIBLE ONES (WATER PARTICLE)
IS CALLED BROWNIAN MOTION.
Core
+supplement

13. APPARATUS FOR MEASURING
MASS TIME AND TEMPRATURE MEASURING VOLUME
• FOR LIQUIDS
VOLUMES CEMTIMETER CUBE /DECIMETER
CUBE
• 1 DM3=1000CM3
• MEASURING CYLINDER
• VOLUMETRIC PIPETTE
• BURETTE VOLUMETRIC FLASK
• FOR GASES
• GAS SYRINGE
• MASS KILOGRAM KG /GRAM G
• BALANCE TOP PAN BALANCE/DIGITAL BALANCE
• TIME SECONDS S
• STOP WATCH STOPWATCH /DIGITAL STOP
WATCH
• TEMPRATURE DEGREE CELSIUS C
TERMOMETER MERCURY
THERMOMETER/DIGITAL THERMOMETER

14. MEASURING VOLUMES

15. ACCURACY
• REPEAT YOUR
MEASUREMENT
• USE APPARATUS WITH
SMALL SCALE DIVISIONS
• USE THE APPARATUS
CAREFULLY

16. THANK
YOU
CHEMISTRY WITH ANUM