Intro to States of Matter

Introduction to States of Matter

• States of Matter: The physical forms in which substances exist, primarily categorized as solids, liquids, and gases.

Solids

• Characteristics:

  • Definite Mass

  • Definite Shape

  • Definite Volume

• Particle Arrangement:

  • Particles are tightly packed in fixed positions.

  • Vibrate in place.

  • Expand slightly when heated.

  • Not compressible.

• Energy: Low energy compared to liquids and gases.

Liquids

• Characteristics:

  • Definite Mass

  • Indefinite Shape (takes the shape of its container)

  • Definite Volume

• Particle Arrangement:

  • Particles are close together but can move past each other.

  • Expand slightly when heated.

  • Slightly compressible.

• Energy: Medium energy level.

Gases

• Characteristics:

  • Definite Mass

  • Indefinite Shape (fills its container)

  • Indefinite Volume

• Particle Arrangement:

  • Particles are much further apart compared to solids and liquids.

  • Vibration is more than in solids or liquids.

  • Easily compressible and expand significantly when heated.

• Energy: High energy, facilitating movement.

Changing States of Matter

• Phase Changes: Involve the organization of particles.

  • Energy Change:

  • Adding or removing energy (temperature) influences particle motion.

  • As particles gain energy, they move further apart; as they lose energy, they come closer together.

  • Interaction between energy change and attractive forces (Intermolecular Forces, IMF) results in phase changes.

Phase Changes

• Types of Phase Changes:

  • Sublimation: Solid to gas

  • Melting: Solid to liquid

  • Freezing: Liquid to solid

  • Vaporization: Liquid to gas

  • Condensation: Gas to liquid

  • Deposition: Gas to solid

Vaporization

• Definition: The process of a liquid transitioning to a gas.

• Vapor Pressure:

  • The force exerted by vapor in equilibrium with its liquid phase.

  • IMF Influence:

  • Stronger IMF leads to lower vapor pressure and more energy required to vaporize.

  • Weaker IMF leads to higher vapor pressure and less energy needed for vaporization.

  • Two types:

  1. Boiling: Liquid to gas when vapor pressure equals atmospheric pressure.

  2. Evaporation: Particles at the surface of a liquid gain enough energy to escape.

Boiling vs. Evaporation

• Boiling:

  • Occurs throughout the liquid.

  • Requires energy to overcome IMF.

  • At sea level, the boiling point of water is 100 °C.

• Evaporation:

  • Occurs at the surface when particles gain sufficient energy.

Condensation

• Definition: Gas to liquid transition by reducing temperature and particle speed.

• Process:

  • Energy removal leads gas particles to lose energy, causing them to come closer together.

  • Decrease in temperature

Freezing and Melting

• Freezing:

  • Liquid to solid transition by lowering temperature and particle speed (removing energy).

  • Decrease in temperature

• Melting:

  • Solid to liquid transition by increasing temperature and particle speed (adding energy).

  • increase in temperature

Sublimation and Deposition

• Sublimation:

  • Solid to gas transition by increasing energy (temperature).

  • (Dry ice)

• Deposition:

  • Gas to solid transition by decreasing energy (temperature).

Heating and Cooling Curves

• Graphical Representation: Shows temperature changes over time as heat is added/removed during phase changes.

• Key Points:

  • Temperature remains constant during phase changes.

  • Matter exists in both phases during these changes.

  • Boiling point requires more energy than melting/freezing point.

  • Distinction between kinetic energy and potential energy.

  • Slope indicates specific heat capacity.

  • -Specific heat capacity - amount of heat required to raise the temperature of onoe gram of a substance by one degree celsius (j/(g°C).

  • Gas-liquid transitions require the most energy.

Cooling Curve Analysis

• States of Matter at Points on Curve:

  • Gas

  • Gas and Liquid

  • Liquid

  • Liquid and Solid

  • Solid

• Identify Phase Changes at each plateau (e.g., condensation, freezing).

Example Problem

• Water Boiling and Freezing:

  • Boiling Point: 100 °C

  • Freezing Point: 0 °C

  • Draw the corresponding cooling curve for water to illustrate state transitions.

Practice

• Continuous practice is essential to master the concepts of phase changes, states of matter, and their properties. Keep practicing!

more notes:

hydrogen bonding: strongest imf, nitrogen oxygen or flourine connects with an oxygen

dipole dipole force: second strongest imf, between polar molecules, normally not symetrical vsepr shape

london dispersion forces: weakest imf, between non polar molecules, mostly symetrical vsper shape