L8 - Diffusion

Lesson 1 - What is IGCSE Chemistry?
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Lesson 8 - Diffusion
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Slide 1: Slide
ChemistrySecondary Education

This lesson contains 27 slides, with interactive quiz and text slides.

time-iconLesson duration is: 55 min

Items in this lesson

Lesson 1 - What is IGCSE Chemistry?
4
9
Lesson 8 - Diffusion

Slide 1 - Slide

Today, I'm going to...
  • know about diffusion in liquids and gases,
  • be able to describe what happens during diffusion using the KPT, and
  • understand why diffusion happens at different rates.
Lesson 8 - Diffusion

Slide 2 - Slide

  • I can define diffusion.
  • I can describe the kinetic energy and movement of particles during diffusion. 
  • I can describe the effect of higher relative molecular mass on the rate of diffusion of gases.
  • I can describe the effect of lower relative molecular mass on the rate of diffusion of gases.
I am successful if...

Slide 3 - Slide

Slide 4 - Slide

  • Prepare your blue or black pen.
  • Open your Workbook on page 3.
  • Complete Focus 2 and Practice 3.
  • You only have minutes to complete your responses.
Workbook Exercise
timer
3:00

Slide 5 - Slide

ANSWERS

Slide 6 - Slide

ANSWERS
B
C
A
D

Slide 7 - Slide

ANSWERS
B
C
A
D
impossible

Slide 8 - Slide

Slide 9 - Slide

Structures of solids, liquids and gases
KPT
SOLID
LIQUID
GAS
Kinetic energy of particles
Low energy
Medium energy
High energy
Motion of particles
Vibrating at a fixed position
Moving slide past each other
Moving freely and quickly
Arrangement of particles

Regular, in rows
Irregular
Irregular
Separation of particles
Close together, (all) touching
Close together, (some) touching
Far apart
Forces between particles
van der Waals forces
cohesive forces
NO force between particles

Slide 10 - Slide

Kinetic Particle Theory
Kinetic energy
Motion 
Arrangement
Forces
Separation

Slide 11 - Slide

Slide 12 - Slide

Slide 13 - Slide

Method
Investigating diffusion in liquids
  1.  Add 20 cm3 of room temperature water to Petri dish A.
  2.  Add 20 cm3 of warm water to Petri dish B.
  3.  Using a spoon, simultaneously add a small amount of potassium permanganate to the middle of Petri dishes A and B.
In which water does the solid diffuse faster?

Slide 14 - Slide

Slide 15 - Link

Method
Investigating diffusion of bromine in air
  1.  Add two drops of liquid bromine to a test tube and put a rubber cork to seal it.
  2.  Start the stopwatch immediately after closing.
  3. Observe.
  4.  Stop the stopwatch once the gas occupies the whole test tube.
How long do two drops of bromine liquid diffuse in a test tube?

Slide 16 - Slide

Slide 17 - Slide

Key Question
  • Which fume has a greater rate of diffusion: hydrogen chloride or ammonia?
Background information:
  • When ammonia and hydrogen chloride gases meet in a sealed tube, they react to form a white smoke ring of ammonium chloride. The mass of ammonia gas is 17.0 g/mol, and the mass of hydrogen chloride gas is 36.5 g/mol.
Hypothesis:
  • ___________________________________________
SDA 1.2 (Practical): Investigating the rate of diffusion

Slide 18 - Slide

Risks
  • Corrosive [C] chemical: Hydrochloric acid
  • Corrosive [C] chemical: Aqueous ammonia

Safety precautions:
  • Wear a laboratory coat throughout the experiment.
  • Tie your long hair.
  • Avoid smelling the chemicals directly. WAFT, if required.
  • Wear safety glasses throughout the experiment.
  • Wear safety gloves.

Slide 19 - Slide

Method

  1.  Put the soaked cotton wool with hydrochloric acid in the bottom of the test tube using forceps.
  2.  Put the soaked cotton wool with aqueous ammonia near the mouth of the test tube.
  3.  Seal the test tube with a rubber stopper.
  4.  Observe.
  5.  Record your observations on the datasheet.

Slide 20 - Slide

Slide 21 - Slide

Slide 22 - Slide

  • I can define diffusion.
  • I can describe the kinetic energy and movement of particles during diffusion. 
  • I can describe the effect of higher relative molecular mass on the rate of diffusion of gases.
  • I can describe the effect of lower relative molecular mass on the rate of diffusion of gases.
I am successful if...

Slide 23 - Slide

Self-check
  • Open your notebook.
  • Look for this.
  • Read.
  • Reflect.
  • Complete.

Slide 24 - Slide


Name something you did not know before this lesson, 
but NOW you do! 

Slide 25 - Open question

timer
5:00

Slide 26 - Slide

timer
5:00

Slide 27 - Slide