Particle Model of Matter Revision Guide

4.3 Particle Model of Matter

1) Three Main States of Matter

• The three states of matter are:
  • Solid
  • Liquid
  • Gas

2) Particle Arrangement of the Three States of Matter

(Illustrations can be included in physical notes. Describe the arrangement):

• Solid: Particles are closely packed in a fixed, orderly arrangement.
• Liquid: Particles are close together but can move past one another, forming a less orderly arrangement.
• Gas: Particles are far apart with no fixed arrangement, moving freely in all directions.

3) Properties of Particles in a Solid

• Strong Force of Attraction: Particles are held tightly together by strong intermolecular forces.
• Vibration on the Spot: Particles vibrate in place but do not move from their fixed positions.
• Fixed Pattern: The arrangement of particles is orderly and structured.
• Cannot be Compressed: Solids have a definite shape and volume, making them inelastic to compression.
• Cannot Take the Shape of a Container: Solids retain their shape irrespective of the container they are in.

4) Properties of Particles in a Liquid

• Weak Force of Attraction: Particles have a weaker intermolecular attraction compared to solids.
• Can Move Over Each Other: Particles can slide past one another, allowing liquids to flow.
• Cannot be Compressed: Liquids also maintain a definite volume, making them inelastic to compression.
• Can Take the Shape of a Container: Liquids assume the shape of the container they occupy while maintaining a constant volume.

5) Properties of Particles in a Gas

• Very Weak Force of Attraction: Intermolecular forces are negligible, allowing for significant particle separation.
• Can Move Freely: Particles in a gas move independently and rapidly in all directions.
• Can be Compressed: Gases can be compressed to occupy smaller volumes due to large spaces between particles.
• Can Take the Shape of a Container: Gases expand to fill the entirety of their container, regardless of shape and volume.

4.3.1.1 Density of Materials

6) Definition of Density

• Density: The term density refers to the measure of how much matter is contained in a specific volume. It can be mathematically defined as:
  $ext{Density} = \frac{ ext{Mass}}{ ext{Volume}}$.

The National Grid

4.2.4.3

47) What is the National Grid?

• The National Grid is a system of cables and transformers designed to connect power stations to consumers, facilitating the distribution of electricity across wide areas.

48) Step-Up Transformers

• Purpose:
  • Used to increase the potential difference from the power station to the transmission cables.
  • Reduces energy losses through heating of the wires since the current is kept low during transmission.

49) Step-Down Transformers

• Purpose:
  • Used to decrease the potential difference for safe domestic usage.
  • Ensures electrical safety by lowering high voltages to safer levels for household appliances and wiring.

50) Efficiency of the National Grid System

• The National Grid system is an efficient way to transfer energy because:
  • It transmits a large amount of power at a high potential difference and at as low a current as is practically possible.
  • This practice significantly reduces energy lost due to heating in the wires and surrounding environment, enhancing the overall efficiency of energy transmission.