Characteristics of Matter: Interparticle Spaces and Motion

Physical Nature of Matter

• Matter is defined as any substance that has mass and volume and can be perceived by senses.
• Experimental study shows that matter is made up of tiny particles that can divide into smaller particles.

Characteristics of Particles of Matter

• Particles of matter have interparticle spaces between them.
• Particles of matter are in continuous motion due to kinetic energy, and the motion increases with temperature.
• Particles of matter have interparticle force of attraction that keeps them together.

States of Matter

Solid State

• Has definite shape and volume
• Mostly incompressible and rigid

Liquid State

• Has indefinite shape and definite volume
• Mostly incompressible and has fluidity

Gaseous State

• Has indefinite shape and volume
• Easily compressible and has fluidity

Interconversion of States of Matter

• Interconversion can be done by changing temperature or pressure.
• Decrease in temperature can cause deposition (gas to solid).
• Increase in temperature can cause sublimation (solid to gas).
• Increase in pressure can decrease interparticle space.

Evaporation

• Evaporation is the process of converting a liquid into a gas at any temperature below its boiling point.
• It is a surface phenomenon, unlike boiling which is a bulk phenomenon.
• Factors affecting evaporation include:
  • Temperature: increase in temperature increases the rate of evaporation
  • Humidity: increased humidity decreases the rate of evaporation
  • Wind speed: increased wind speed increases the rate of evaporation
  • Surface area: increased surface area increases the rate of evaporation