The three states of matter are solid, liquid, and gas, determined by the arrangement and movement of particles.
Solids have fixed shape and volume, liquids have fixed volume but take the shape of the container, and gases have no fixed shape or volume.
Phase changes occur when thermal energy is added or removed, causing changes in particle arrangement and movement.
The states of matter and their changes have numerous everyday applications.
Understand the key properties and be able to explain phase changes to succeed on exams.
The Three States of MatterAll substances in the universe can exist in one of three states: solid, liquid, or gas. These states are determined by the arrangement and movement of the particles (atoms or molecules) that make up the substance.### SolidsSolids are characterized by a fixed shape and volume. The particles in a solid are packed closely together and vibrate in fixed positions. They have a high density and are generally incompressible.**Properties of Solids:**- Fixed shape and volume- Particles arranged in a regular, organized pattern- Particles have low kinetic energy and vibrate in fixed positions- High density and incompressible- Examples: ice, metal, wood, rock### LiquidsLiquids have a fixed volume but take the shape of the container they are in. The particles in a liquid are still closely packed but can move around each other more freely than in a solid.**Properties of Liquids:**- Fixed volume but take the shape of the container- Particles have more kinetic energy and can flow past each other- Higher density than gases but lower than solids- Partially incompressible- Examples: water, oil, mercury, alcohol### GasesGases have no fixed shape or volume, and the particles are far apart and move randomly. Gases can be easily compressed and expand to fill the entire container.**Properties of Gases:**- No fixed shape or volume- Particles have high kinetic energy and move randomly- Low density and easily compressible- Easily expand to fill the entire container- Examples: air, oxygen, carbon dioxide, helium## Changes in StateThe state of a substance can change through the addition or removal of thermal energy (heat). The three main changes of state are:1. **Melting**: The transition from solid to liquid state.2. **Boiling/Evaporation**: The transition from liquid to gas state.3. **Condensation**: The transition from gas to liquid state.During these phase changes, the arrangement and movement of the particles change, but the chemical composition remains the same.**Melting**When a solid is heated, the particles gain kinetic energy and begin to break free from their fixed positions. This causes the solid to transition into a liquid state. The temperature at which this occurs is called the melting point.**Boiling/Evaporation**As a liquid is heated, the particles continue to gain kinetic energy until they have enough energy to overcome the attractive forces between them. This causes the liquid to transition into a gas state. The temperature at which this occurs is called the boiling point.**Condensation**When a gas is cooled, the particles lose kinetic energy and the attractive forces between them become stronger. This causes the gas to transition back into a liquid state. The temperature at which this occurs is called the dew point.## Everyday Examples and ApplicationsThe states of matter and their changes are essential in many everyday applications:- Solid water (ice) is used for cooling and refrigeration.- Liquid water is used for drinking, cooking, and cleaning.- Gaseous water (steam) is used to power turbines and heat buildings.- Metals are often used in their solid state for construction and manufacturing.- Liquid fuels like gasoline are used to power vehicles.- Gases like oxygen and nitrogen are used in various industrial and medical applications.## Exam Tips and Common Mistakes- Remember the key properties that distinguish solids, liquids, and gases.- Understand how the arrangement and movement of particles change during phase changes.- Be able to identify and explain everyday examples of the states of matter and their applications.- Common mistakes include confusing the properties of the different states and incorrectly describing the changes that occur during phase changes.- Practice identifying the state of matter and predicting how it will change under different conditions.## Key Points- The three states of matter are solid, liquid, and gas, determined by the arrangement and movement of particles.- Solids have fixed shape and volume, liquids have fixed volume but take the shape of the container, and gases have no fixed shape or volume.- Phase changes occur when thermal energy is added or removed, causing changes in particle arrangement and movement.- The states of matter and their changes have numerous everyday applications.- Understand the key properties and be able to explain phase changes to succeed on exams.