Kinetic particle theory explorer
Heat ice to steam and cool it back while you watch the particles and the heating curve, then race ammonia against hydrogen chloride along a tube.
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Learning goals
- describe the solid, liquid and gaseous states of matter and explain their interconversion in terms of the kinetic particle theory and of the energy changes involved.
Learning objectives
- describe the solid, liquid and gaseous states of matter and explain their interconversion in terms of the kinetic particle theory and of the energy changes involved.
- describe and explain evidence for the movement of particles in liquids and gases (the treatment of Brownian motion is not required)
- explain everyday effects of diffusion in terms of particles, e.g. the spread of perfumes and cooking aromas; tea and coffee grains in water
- state qualitatively the effect of molecular mass on the rate of diffusion and explain the dependence of rate of diffusion on temperature.
10 g of water heated at 200 W. After 0 s it is at −20 °C and is solid: particles vibrate about fixed positions.
- Temperature
- −20 °C
- State
- solid
- Energy transferred
- 0.0 kJ
- Mean speed of NH₃
- — m/s
- Mean speed of HCl
- — m/s
- Ring formed after
- — s
- Ring from NH₃ end
- — cm
Try this
0 of 4 doneHeat the ice and watch the thermometer while it melts. (not done yet)
The temperature stays at 0 °C until all the ice has melted. The energy overcomes the attractions holding particles in fixed positions; it does not make them move faster.
Boil all the water, then do it again with a different heater power. (not done yet)
The stronger heater shortens the flat parts but the water still boils at 100 °C. A pure substance has a fixed boiling point.
Release ammonia and hydrogen chloride and wait for the white ring. (not done yet)
The ring of NH₄Cl forms nearer the HCl end. NH₃ (Mr 17) is lighter than HCl (Mr 36.5), so its particles move faster and it diffuses faster.
Form the ring at 25 °C and again at 200 °C. (not done yet)
At the higher temperature the particles move faster, so both gases diffuse faster and the ring forms sooner, at about the same place.