Physics Chapter: Heat and Temperature

Heat and Temperature

• Heat (q) is the flow or transfer of thermal energy.
• Temperature (T) is a measure of the average kinetic energy of particles in a substance.
• Phase transitions are physical changes involving heat transfer (e.g., melting, boiling).

Phase Transitions and Energy Calculations

• Weight Loss Calculation: A person wishing to lose 5 pounds of fat needs to walk approximately 175 miles (or 17,500 minutes at 3 mi/h).
• Energy for Ice: Melting and warming 145 grams of ice at 0.0 °C to 37.0 °C requires approximately 16.3 kcal of heat.

Specific Heat Capacity

• To calculate heat energy transfer (Q), use the formula: Q = m × SH × ΔT, with mass (m), specific heat capacity (SH), and change in temperature (ΔT).
• For phase transitions, use the heat of fusion or vaporization as needed.

Important Values (Memorize)

• Blood pH: 7.35-7.45
• Water density: 1.00 g/cm³ at 4°C
• Heat of vaporization of water: 540 cal or 2260 J
• Heat of fusion of water: 80 cal or 334 J

Significant Figures (Chapter 4)

• Rules: All non-zero digits are significant. Interior zeros are significant; leading zeros are not; trailing zeros in a decimal number are.
• Multiplication/Division: Result has same number of sig figs as the factor with fewest sig figs.
• Addition/Subtraction: Result has same number of decimal places as the quantity with fewest dec places.

Atomic Structure and Theory

• Isotopes (Memorize): 12C, 13C, and 14C exhibit different neutron counts while maintaining the same atomic number (protons).
• Protons: Positively charged particles in the nucleus.
• Neutrons: Neutral particles in the nucleus.
• Electrons: Negatively charged particles orbiting the nucleus.
• Atomic mass unit (amu): Defined as 1/12 the mass of a carbon-12 atom.
• The mole (mol) represents 6.022 x 10²³ entities (Avogadro's number).
• Atomic number is determined by the number of protons in an atom.
• Boiling of water: 100°C (373.15 K); Freezing point of water: 0°C (273.15 K).

SI Prefixes (Memorize)

• kilo (k) = 10³
• centi (c) = 10^-2
• milli (m) = 10^-3
• micro (µ) = 10^-6
• nano (n) = 10^-9

Radioactive Decay (Chapter 5)

• Alpha (α): Shielded by paper or clothing.
• Beta (β): Shielded by lab coat or gloves.
• Gamma Rays: Shielded by lead or thick concrete.
• Alpha Decay: Emission of an alpha particle, decreasing atomic mass.
• Beta Emission: Neutron converts to proton and electron, increasing atomic number.
• Positron Emission: Proton converts to neutron and positron, decreasing atomic number.
• Alpha particle: 4/2 He
• Beta particle: 0/-1e
• Positron: 0/1 e
• Gamma rays: 0/0 y
• Radiation Units: rem = rad x factor (factor depends on radiation type).

Half-life Problems

• To solve half-life problems, use the formula: A_t = A₀ / (2ⁿ), where A_t is amount remaining, A₀ is initial amount, n is the number of half-lives (time elapsed/half-life).

Chemical Bonding and Intermolecular Forces (Chapters 6 & others)

• Lewis Structures: Diagrams showing bonding and lone pairs in molecules.
• Electronegativity: Measure of an atom's attraction for bonding electrons, influencing bond polarity.
• Hydrogen Bonds: Strong dipole-dipole attractions in molecules with H bonded to N, O, or F.
• Dipole-Dipole Attractions: Interactions between polar molecules.
• Dispersion Forces: Weak intermolecular forces due to temporary dipoles.
• Hydroxide: OH⁻; Sulfate: SO₄²⁻; Nitrate: NO₃⁻; Ammonium: NH₄⁺; Carbonate: CO₃²⁻
• Electronegativity Scale: 0-0.3 (nonpolar); 0.4-2 (polar); >2 (ionic).
• Naming Covalent Compounds: Use prefixes like mono, di, tri for elements in covalent compounds.

Organic Chemistry (Chapter 12)

• Organic compounds are primarily carbon and hydrogen, found in various products (oil, medicine, etc.).
• Every carbon atom forms four bonds.
• IUPAC Naming: Standard system for naming organic compounds.
• Hydrocarbons: Alkanes (single bonds); Alkenes (double bonds); Alkynes (triple bonds); Cycloalkanes (ring structures)
• Isomers: Molecules with same molecular formula but different bonding, thus different properties (cis-trans and structural isomers).

Chemical Reactions (Chapter 7)

• Combustion: Reaction with oxygen, producing CO₂ and H₂O.
• Synthesis: Two or more reactants form a product.
• Decomposition: A compound breaks down into simpler substances.
• Exchange: Exchange of components.
• Balancing Equations: Ensure equal atoms of each element on both sides of an equation.
• Limiting Reagents: Reactant that is completely used, limiting product amount.
• % Yield: Ratio of actual yield to theoretical yield, expressed as a percentage.
• Mole Calculations: Converting mass and moles, determining atoms/molecules.
• Energy Changes: Exothermic reactions release heat, endothermic reactions absorb heat.

Gases (Chapter 8)

• Temperature (T): Average kinetic energy of gas particles.
• Volume (V): Space occupied by gas.
• Amount (n): Number of moles of gas.
• Pressure (P): Gas particle collisions with container walls.
• Boyle's Law: P₁V₁ = P₂V₂ (constant T)
• Gay-Lussac's Law: P₁/T₁ = P₂/T₂ (constant V)
• Charles's Law: V₁/T₁ = V₂/T₂ (constant P)
• Ideal Gas Law: PV = nRT; STP (Standard Temperature and Pressure )= 0°C (273K) and 1 atm (760 mmHg)
• Breathing: Inhalation increases lung volume, decreasing pressure, letting air enter. Exhalation decreases lung volume, increasing pressure, forcing air out.

Solutions and Solubility (Chapter 9)

• Solubility of most solids increases with temperature and gases decreases with temperature.
• Osmotic Pressure in blood is important for red blood cells
• Preparing solutions: Calculate mass of solute using molarity formula M = moles of solute/liters of solution.
• Diluting solutions: Use M₁V₁ = M₂V₂
• Strong Electrolyte (eg HCl) ~=100% products form.
• Weak Electrolyte: Less then 100% products form.

This quiz covers essential concepts related to heat and temperature, including heat transfer, specific heat capacity, and phase transitions. Students will also learn how to perform energy calculations and memorize important physical values. Test your understanding of these fundamental principles of physics.