Temperature and Heat Study Notes PDF

**Temperature and Heat Study Notes** **Temperature** Temperature is defined as the measure of the average kinetic energy of all the particles in an object. The temperature of an object is influenced by the mass and speed of its atoms. **Temperature Scales** There are three primary temperature sc...

**Temperature and Heat Study Notes** **Temperature** Temperature is defined as the measure of the average kinetic energy of all the particles in an object. The temperature of an object is influenced by the mass and speed of its atoms. **Temperature Scales** There are three primary temperature scales: - **Fahrenheit:** Developed by Daniel Gabriel Fahrenheit, this scale is primarily used in American weather reports, home thermostats, and fever thermometers. - **Celsius:** Created by Anders Celsius, this scale assigns 0°C to the freezing point of pure water and 100°C to its boiling point. It is commonly used to measure body temperature. - **Kelvin:** Introduced by William Thomson, 1st Baron Kelvin, this scale includes the concept of absolute zero, which is the lowest possible temperature. The zero point on the Kelvin scale is absolute zero. Key temperature conversions include: - Freezing Point: 0°C = 273.15 K = 32°F - Boiling Point: 100°C = 373.15 K = 212°F **Formulas for Temperature** To convert between different temperature scales, the following formulas are used: - Fahrenheit to Celsius: °F = °C (9/5) + 32 - Celsius to Fahrenheit: °C = 5/9 (°F -- 32) - Celsius to Kelvin: K = °C + 273.15 **Heat** Heat is defined as the energy that flows from an object at a higher temperature to an object at a lower temperature. The SI unit for heat is the Joule (J), while the Calorie is another unit commonly used, especially in nutrition to specify the energy content of foods. **Thermal Expansion** Thermal expansion refers to the increase in size of an object as it is heated. This phenomenon occurs in all gases, liquids, and most solids when their temperature increases. **Thermal Equilibrium** Thermal equilibrium is achieved when heat energy flows between two objects until they reach the same temperature. At this point, the two objects are said to be in thermal equilibrium. **Formulas for Heat** The following formulas are used to calculate heat and specific heat: - For the required amount of heat: **Q = mcΔT** - Q = required amount of heat - m = mass of matter - c = specific heat of matter - ΔT = change in temperature (Tf -- Ti) - For specific amount of heat: **C = Q/mΔT** **Particle Nature of Matter Study Notes** **Kinetic Molecular Theory** All matter is composed of atoms or molecules formed by atoms joining together. The key points of the kinetic molecular theory include: - Particles in motion possess kinetic energy. - As particles gain energy, their motion increases. - Particles are in constant and random motion. **Properties of Solid, Liquid, and Gas** **Solids** Solids have distinct characteristics: - Definite shape and volume. - Molecules are tightly packed with minimal movement. - Molecules are arranged in a regular pattern and are generally incompressible. - Molecules vibrate but cannot change position due to limited space. - When heated, molecules may expand. **Types of Solids** 1. **Crystalline Solid:** - Composed of units called crystals. - Arranged in definite patterns. - Bounded by planes or faces. - Examples: sugar, salt, diamond. 2. **Amorphous Solid:** - Particles are randomly arranged. - Molecules are non-organized. - Examples: glass, rubber, candle wax, plastics. **Liquids** Liquids exhibit the following properties: - Definite volume but indefinite shape, taking the shape of their container. - Molecules are relatively close and slide over each other. - Molecules slightly expand when heated. **Properties of Liquid** 1. **Fluidity:** Ability to flow. 2. **Viscosity:** Measure of resistance to flow (thickness). 3. **Capillary Action:** Rising of liquid in a tube due to adhesive forces between molecules. 4. **Surface Tension:** Energy required to increase the surface area of a liquid. **Gases** Gases have unique characteristics: - Molecules occupy all available space. - Indefinite shape and volume. - Molecules are far apart and move freely. - Molecules expand significantly when heated. **Properties of Gas** 1. **Volume:** No definite volume. 2. **Pressure:** Movement of molecules creates force over an area, measurable with a barometer. 3. **Temperature:** Measure of average kinetic energy; increased temperature causes gas expansion. **Phase Changes in Water** Water undergoes several phase changes: - **Melting:** Solid to liquid. - **Freezing:** Liquid to solid. - **Evaporation:** Liquid to gas. - **Sublimation:** Solid to gas. - **Condensation:** Gas to liquid. - **Deposition:** Gas to solid. **Phase Diagram** A phase diagram illustrates the states of matter in relation to pressure and temperature: - **Triple Point:** The point where gas, liquid, and solid coexist. - **Critical Point:** The point where a substance is indistinguishable between liquid and gas. - **Fusion Curve:** Represents the transition between liquid and solid states. - **Vaporization Curve:** Represents the transition between gas and liquid states. - **Sublimation Curve:** Represents the transition between gas and solid states.