IGCSE Coordinate Science 1
Particle Movement and
Rates of Reactions
P04, C7.1, B03 Key Notes
Review
• List the three major states of matter &
brainstorm everything you can remember
about each one.
Simple Kinetic Molecular Model of
Matter
States of Matter
The States of Matter
• Solids – occupies a fixed volume and has a
a.) Solids
- occupies a fixed volume and has a
fixed
shape.
fixed shape
The particles are
packed closely
together. The
particles cannot
move around but
they do vibrate
about a fixed
position.
The
b.) Liquids - occupies a fixed volume but
they do vibrate
about a fixed
position.
States of Matter
• Liquids – occupies a fixed volume but takes
b.) Liquids - occupies a fixed volume but
the shape of its
container.
takes
the shape of its container
The particles are packed
slightly less closely
together compared to
solids. The particles have
the opportunity to move
around within the bulk of
the liquid. The particles
are both vibrating and
moving from place to
place.
c.) Gases - expands to fill its container and
solids. The particles have
the opportunity to move
around within the bulk of
the liquid. The particles
are both vibrating and
moving from place to
place.
States of Matter
• Gasses – expands to fill its container and takes
c.) shape
Gases -ofexpands
to fill its container and
the
its container.
takes the shape of its container
The particles are widely
separated from one
another. They are no
longer in contact, unless
they collide with each
other. They are now
moving freely about,
bouncing off one another
and off the walls of the
container.
• What can you say about the distances
between molecules of solids, liquids and
gasses?
• What can you say about the forces between
molecules of solids, liquids, and gasses?
• Temperature – the measure of the average
kinetic energy (KE)of all the particles in an
object. (KE refers to energy due to motion)
• Pressure – amount of force per unit area.
• Volume – amount of space occupied by an
object.
Simulation
• Based on the simulation, what can you say about the
relationship between:
– Temperature of a gas vs. motion of its molecules?
• Increase in temperature will increase the motion of its molecules.
– Pressure of a gas vs. motion of its molecules?
• When the number of molecules and the volume of the container is
kept constant, increasing the temperature will increase the motion
of the molecules thus increasing pressure (increasing the chances
for the molecules to hit the walls of the container)
– The effect of a change in temperature to the pressure of
the gas at constant volume?
• When the number of molecules and the volume of the container is
kept constant, increasing the temperature will increase the motion
of the molecules, thus increasing pressure (increasing the chances
for the molecules to hit the walls of the container)
Boyle’s Law
• The volume of a fixed mass of gas is inversely
proportional to its pressure, provided its
temperature remains constant.
p1V1 = p2V2
initial pressure x initial volume =
final pressure x final volume
( pV = constant )
Example
• A cylinder contains 50cm3 of air at a pressure
of 120 kPa. What will its volume be if the
pressure on it is increased to 400 kPa?
Evaporation vs. Boiling
Evaporation
* both are changes of the state of matter
from liquid toisgas
• Evaporation
not boiling.
* A liquid boils at its boiling point, but
• It
is the escape
of moreatenergetic
evaporation
happens
a lower molecules
from
the surface
of athe
liquid
temperature,
below
boiling point.
temperature, below the boiling point.
temperature, below the boiling point.
Factors
affecting
evaporation
Factors Affecting Evaporation
Factors Affecting Evaporation
•
Temperature:
Factors
Affecting
Evaporation
1.)
Temperature
1.) Temperature
1.) Temperature
• Surface area:
2.) Surface Area
2.) Surface Area
3.) Air flow over a surface
• 2.)
Air Surface
flow over
a surface:
Area
3.) Air flow over a surface
Explain this statement:
• Evaporation is a cooling process.
IN
• Write a few sentences explaining how
temperature, pressure, and motion of
molecules in a container of fixed volume are
related.
Chemistry (C7.1)
Reaction Rates Labs
• Follow the directions carefully for the lab.
• You may have more than one time trial going
on at one time as long as you have enough
timing devices!
• Thoroughly clean your test tubes, baby
beakers, and measuring cylinders well
between labs so you don’t contaminate your
next set of chemicals.
Rates of Reaction
• Explain the concept of “rate”
• Influenced by:
–
–
–
–
Temperature
Concentration
Surface area
Catalysts
• Explain each of these at the particle level using
this simulation:
http://phet.colorado.edu/en/simulation/reaction
s-and-rates
Explosions!
• Read pg. 136 – 137 and answer Q3 on pg. 137
Experimental Design
• Adding magnesium to hydrochloric acid (HCl)
produces hydrogen gas.
– If you were to repeat this experiment, how could
you collect quantitative (numerical) data on the
rate of reaction?
• Devise a method for data collection.
• Available materials include: test tubes, beakers,
syringe, tubing, stopper with holes in them, measuring
cylinders, pipets, HCl, magnesium, markers, rulers,
stopwatches
Methods for Calculating Rate of Gas
Production: Collecting Gas in a Syringe
Methods for Calculating Rate of Gas
Production: Collecting Gas over Water
Graduated Cylinder for
measuring volume of gas
produced
Biology (B03)
Catalysts
• Catalysts: An agent which increases the
reaction rate but which itself remains
unchanged.
• Enzymes: Proteins that function as
biological catalysts.
Enzymes
Enzyme
1. Substrates
bind to enzyme
2. Substrates are
converted into
products
3. Products are
released
Active Site
2
Enzyme -substrate
complex
Enzyme videos
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/ch
apter2/animation__how_enzymes_work.html
• http://www.kscience.co.uk/animations/anim_
2.htm
Regulating Enzymes
• Denatured: When an enzyme loses its 3D
shape, so the active site can no longer bind to
the substrate.
• Enzyme activity is affected by:
– Temperature
• 37oC is usually optimal for enzymes in humans. Why?
– pH
Your aim is to be able not just to recreate the graphs, but to
annotate and explain their shape in terms of what is happening
at a molecular level.
Catalase Lab
• You must wear lab safety goggles, apron, and
gloves the whole time.
• Do Investigation 1, and then finish either
Investigation 2 or 3 today.