PHYS 1100 Exam 3 Review: Atomic Nature of Matter, Solids, Liquids, Gases, and Thermal Physics

Chapter 11: The Atomic Nature of Matter

Atoms and Subatomic Particles

Atoms are the fundamental building blocks of matter, composed of smaller particles called electrons, protons, and neutrons.

• Atom: The smallest particle of an element that retains its chemical properties. Atoms consist of a nucleus (containing protons and neutrons) surrounded by electrons.

• Electron: A tiny, negatively charged particle found outside the nucleus.

• Proton: A positively charged particle located in the nucleus.

• Neutron: An electrically neutral particle also found in the nucleus.

Elements, Ions, and Isotopes

• Element: A pure substance consisting of only one type of atom.

• Atomic Number (Z): The number of protons in an atom, which uniquely identifies the element. In a neutral atom, the number of electrons equals the number of protons.

• Ion: An atom with an unequal number of protons and electrons, resulting in a net electric charge.

• Isotope: Atoms of the same element (same number of protons) but with different numbers of neutrons.

Antimatter and Annihilation

• Antimatter: Material composed of atoms with negatively charged nuclei and positively charged electrons (positrons).

• Annihilation: When matter and antimatter meet, they are completely converted into radiant energy (e.g., gamma rays).

Chapter 12: Solids – Density

Density and Weight Density

Density is a fundamental property of matter, describing how much mass is contained in a given volume.

• Density (\( \rho \)): The mass per unit volume of a substance. It is independent of the amount of material.

$\text{Density} = \frac{\text{mass}}{\text{volume}}$

• Weight Density: The weight per unit volume of a substance.

$\text{Weight Density} = \frac{\text{weight}}{\text{volume}}$

• Physical Meaning: Density depends on both the mass of the atoms and the spacing between them.

Chapter 13: Liquids

Pressure in Liquids

Liquids exert pressure due to the weight of the fluid above a given point.

• Pressure (\( P \)): The force applied per unit area.

$P = \frac{F}{A}$

• Liquid Pressure: Determined by the weight density of the liquid and the depth below the surface.

$\text{Liquid Pressure} = (\text{weight density}) \times \text{depth} = (\rho_L g) d$

Buoyant Force and Archimedes’ Principle

• Buoyant Force: The net upward force on an object submerged in a fluid, caused by the increase in pressure with depth.

• Archimedes’ Principle: The buoyant force on an immersed object equals the weight of the fluid displaced by the object.

$F_{\text{Buoyant}} = \rho_{\text{fluid}} g V_{\text{submerged}}$

Floatation

• An object floats if it displaces a volume of fluid equal to its own weight.

• If the object's density is greater than the fluid, it sinks; if less, it floats; if equal, it remains suspended.

Pascal’s Principle

• A change in pressure at any point in a confined fluid is transmitted undiminished throughout the fluid.

Surface Tension

• The tendency of a liquid's surface to contract, minimizing surface area due to cohesive forces between molecules.

Chapter 14: Gases

Atmospheric Pressure

Atmospheric pressure is caused by the weight of the air above a given point and varies with elevation and air density.

• Average Atmospheric Pressure at Sea Level: 101 kPa = 100,000 N/m2

Gas Laws

• Boyle’s Law (General Gas Law): For a fixed amount of gas, the relationship between pressure, volume, and temperature is:

$\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$

Buoyancy in Gases (Archimedes’ Principle)

• The buoyant force on an object in a gas equals the weight of the gas displaced.

$F_{\text{Buoyant}} = \rho_{\text{fluid}} g V_{\text{displaced}}$

Bernoulli’s Principle

• The internal pressure in a moving fluid decreases as the speed of the fluid increases.

Chapter 15: Temperature, Heat, and Expansion

Temperature and Heat

• Temperature: A measure of the average translational kinetic energy per molecule in a substance.

• Absolute Zero: The lowest possible temperature, where molecular motion ceases.

• Heat: Energy that flows from a higher temperature object to a lower temperature object.

• Internal Energy: The total energy (kinetic + potential) contained within a substance.

Specific Heat Capacity

• The amount of heat required to change the temperature of 1 kg of a substance by 1°C.

$Q = m c \Delta T$

Thermal Expansion

• Most substances expand when heated due to increased molecular motion.

$\Delta L = L_0 \alpha \Delta T$

• Where \( \Delta L \) is the change in length, \( L_0 \) is the original length, \( \alpha \) is the coefficient of linear expansion, and \( \Delta T \) is the temperature change.

Chapter 16: Heat Transfer

Mechanisms of Heat Transfer

• Conduction: Transfer of heat through direct collisions of particles within a substance (mainly in solids).

• Convection: Transfer of heat by the bulk movement of fluid (liquids or gases).

• Radiation: Transfer of energy via electromagnetic waves (can occur in a vacuum).

Newton’s Law of Cooling

• The rate of heat loss of a body is proportional to the temperature difference between the body and its surroundings.

Greenhouse Effect

• Warming of the Earth due to the atmosphere's selective transmission of shortwave solar radiation and trapping of longwave terrestrial radiation.

Chapter 17: Change of Phase

States of Matter and Phase Changes

• States of Matter: Solid, Liquid, Gas, Plasma

• Evaporation: Liquid to gas at the surface; a cooling process.

• Sublimation: Solid to gas without passing through the liquid phase.

• Condensation: Gas to liquid; a warming process.

• Boiling: Rapid vaporization throughout a liquid; occurs when vapor pressure equals surrounding pressure.

• Melting: Solid to liquid.

• Freezing: Liquid to solid.

Latent Heat

• Latent Heat of Fusion: Energy required to change a substance from solid to liquid (or vice versa).

• Latent Heat of Vaporization: Energy required to change a substance from liquid to gas (or vice versa).

$Q = m L$

• Where \( Q \) is the heat required, \( m \) is the mass, and \( L \) is the latent heat.

Heat Required for Temperature Change

$Q = m c \Delta T$

• Where \( Q \) is the heat, \( m \) is the mass, \( c \) is the specific heat, and \( \Delta T \) is the temperature change.

Example Table: Comparison of Phase Changes

Phase Change	Initial State	Final State	Energy Flow	Latent Heat Involved
Melting	Solid	Liquid	Absorbed	Fusion
Freezing	Liquid	Solid	Released	Fusion
Vaporization (Boiling)	Liquid	Gas	Absorbed	Vaporization
Condensation	Gas	Liquid	Released	Vaporization
Sublimation	Solid	Gas	Absorbed	Sublimation
Deposition	Gas	Solid	Released	Sublimation

Additional info: Table entries for 'Deposition' and 'Sublimation' are inferred for completeness.