Chapter 6 Kinetic Particle Theory

Transcription

1 Chapter 6 Kinetic Particle Theory To understand that matter is made up of small particles which are in constant and random motion. To describe simple model of solids, liquids and gases, in terms of the arrangement and movement of particles.

2 Chapter 6 Kinetic Particle Theory 6.1 Using the Particulate Nature of Matter as a Model 6.2 Models of States of Matter

3 6.1 Using the Particulate Nature of Matter as a Model At the end of this section, you should be able to answer the following questions: What is matter made up of? Can models be used to explain phenomena?

4 6.1 Using the Particulate Nature of Matter as a Model Lesson trigger When dust particles are placed under a beam of light, they appear to be dancing. However, dust particles do not move on their own. They appear to be doing so because of the surrounding air, which is also made up of particles. Click here for a video of dust particles moving in sunlight. What is causing the dust particles to move?

5 6.1 Using the Particulate Nature of Matter as a Model Air, like all other matter, consists of tiny particles. All particles of matter are constantly moving in a random manner and this is known as Brownian motion. The particulate nature of matter can be used to explain this.

6 6.1 Using the Particulate Nature of Matter as a Model Like dust particles, a pollen grain suspended in water would appear to move on its own. The following model explains the Brownian motion. 1. The water particles 2. The are always water particles moving 3. collide Hence, with the pollen randomly. However, the pollen grain appears grain. The to be the water particles pollen moving grain on its is own. are invisible to visible the naked to the naked eye. eye (with the use of a light microscope).

7 6.1 Using the Particulate Nature of Matter as a Model Water and alcohol are made up of particles of different sizes These particles have empty spaces in between them On mixing, smaller particles fill up the spaces in between the larger particles Therefore, volume of the mixture is less than the separate volumes added together.

8 6.1 Using the Particulate Nature of Matter as a Model Thus, the particulate nature of matter is a model used to explain matter. The model of particulate nature of matter is summarised as follows: All matter is made up of small discrete particles. All particles of one pure substance are identical. Particles of all matter are in constant and random motion. This model is used to explain the properties of different states of matter.

9 Chapter 6 Kinetic Particle Theory 6.1 Using the Particulate Nature of Matter as a Model 6.2 Models of States of Matter

10 6.2 Models of States of Matter At the end of this section, you should be able to answer the following questions: What is the model used to explain the arrangement and movement of particles in solids, liquids and gases? How can we compare the properties of solids, liquids and gases (volume, shape, density and ability to be compressed) in terms of how particles move and are arranged?

11 6.2 Models of States of Matter Lesson trigger When blowing air bubbles, the air blown into the the bubble takes the shape of the bubble. The liquid film surrounding the bubble changes in shape to contain the growing amount of air. The bubble wand does not change its shape no matter how hard you blow it.

12 6.2 Models of States of Matter The bubble wand is a solid, the liquid film is a liquid and the air is a gas. These are the three different states of matter. To understand the different properties of each state, we study the particulate nature of matter.

13 6.2 Models of States of Matter Particle Particulate model of a solid Movement Arrangement Physical properties Held together by very strong forces of attraction Unable to move about freely Vibrate about in their fixed positions Packed very closely together A fixed, regular pattern Has a definite shape and volume Occupies the smallest volume Has a higher density than liquids and gases Cannot be compressed

14 6.2 Models of States of Matter Particle Particulate model of a liquid Movement Arrangement Physical properties Held together by strong forces of attraction Able to slide past one another Packed closely together No fixed, regular pattern Has no definite shape Has a fixed volume Occupies more volume than solids Has a lower density than solids Cannot be compressed

15 Particle 6.2 Models of States of Matter Particulate model of a gas Movement Arrangement Physical properties Held together by weak forces of attraction Able to move about freely over long distances Far apart from one another No fixed, regular pattern Has no definite shape or volume Occupies the largest volume Has the lowest density Can be compressed Click here to see an animation of how particles behave in different states. Describe how the particles behave in each state.

16 6.2 Models of States of Matter Particulate model of solid, liquid and gas

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