Chemistry Reviewer For FINALS PDF

Electrochemistry Reviewer 1. Introduction to Electrochemistry Electrochemistry: Branch of chemistry involving the interconversion of electrical energy and chemical energy. Electrochemical Processes: o Redox reactions where electrons are transferred between speci...

Electrochemistry Reviewer 1. Introduction to Electrochemistry Electrochemistry: Branch of chemistry involving the interconversion of electrical energy and chemical energy. Electrochemical Processes: o Redox reactions where electrons are transferred between species. o Can convert spontaneous reactions to electricity or use electricity to drive non- spontaneous reactions. Key Definitions: Oxidation: Loss of electrons, increase in oxidation state. Reduction: Gain of electrons, decrease in oxidation state. Mnemonics: OIL RIG: Oxidation Is Losing, Reduction Is Gaining. LEORA GEROA: Losing Electron, Oxidation, Reducing Agent. Gaining Electron, Reduction, Oxidizing Agent. 2. Balancing Redox Reactions 1. Steps in Acidic Medium: o Separate into half-reactions. o Balance all atoms except H and O. o Balance O with H₂O, H with H⁺, and charges with e⁻. o Combine half-reactions, ensuring electron balance. 2. Steps in Basic Medium: o Follow the same process but add OH⁻ to neutralize H⁺ and form H₂O. Example: Zn + Cu²⁺ → Cu + Zn²⁺ Oxidation: Zn → Zn²⁺ + 2e⁻ Reduction: Cu²⁺ + 2e⁻ → Cu Combined: Zn + Cu²⁺ → Cu + Zn²⁺ 3. Electrochemical Cells Types of Electrochemical Cells: Voltaic (Galvanic) Cells: o Spontaneous reactions generate electrical energy. o Example: Batteries. Electrolytic Cells: o Electrical energy drives non-spontaneous reactions. o Example: Electroplating. Cell Notation Format: Anode | Anode Solution || Cathode Solution | Cathode Example: Zn | Zn²⁺ (1M) || Cu²⁺ (1M) | Cu Mnemonic: OXAN REDCAT Oxidation at Anode Reduction at Cathode 4. Standard Cell Potential (ε⁰) Formula: ε⁰ = ε° (cathode) – ε° (anode) Positive ε⁰: Spontaneous reaction (Galvanic cell). Negative ε⁰: Non-spontaneous reaction (Electrolytic cell). Diagonal Rule: Species with a higher reduction potential oxidizes species with a lower reduction potential (spontaneously). 5. Gibbs Free Energy and Equilibrium Constant Relation to Cell Potential: ΔG = -nFε⁰ o n = number of moles of electrons transferred. o F = Faraday’s constant (96485 C/mol). At Standard Conditions: ΔG⁰ = -nFε⁰  Equilibrium Constant (K): ε⁰ = (RT / nF) ln K → Simplified to 0.0592/n log K at 298K. 6. Nernst Equation for Nonstandard Conditions Formula: ε = ε⁰ – (0.0592/n) log Q Q: Reaction quotient (ratio of product and reactant concentrations). 7. Corrosion Electrochemical process where metals deteriorate (e.g., rust formation in iron). Prevention Methods: 1. Paint/Coatings: Protects surface but can fail if damaged. 2. Passivation: Use of oxidizing agents like nitric acid. 3. Cathodic Protection: Make the metal the cathode using a sacrificial anode. 8. Batteries Types of Batteries: 1. Dry Cell Battery: o Anode: Zinc; Cathode: Carbon rod. o Produces 1.5V. 2. Mercury Battery: o Long-lasting; Used in medical equipment. o Produces 1.3V. 3. Lead Storage Battery: o Used in automobiles. o Produces 12V (6 cells, 2V each). 4. Lithium-Ion Battery: o Lightweight, rechargeable. o Used in electronics. 5. Fuel Cells: o Convert chemical energy to electrical energy (e.g., hydrogen-oxygen fuel cells). 9. Electrolysis Definition: Electrical energy drives nonspontaneous chemical reactions. Examples: o Electrolysis of NaCl: Produces sodium metal and chlorine gas. o Electrolysis of Water: Produces hydrogen and oxygen gases. Quantitative Aspects: Charge Formula: Q = I × t Faraday’s Laws: o 1 mole of electrons carries 96485 C (Faraday constant). o Electrical work: w = -nFε⁰ Equations and Legends Key Equations: 1. Standard Cell Potential: ε⁰ = ε° (cathode) – ε° (anode) 2. Gibbs Free Energy: ΔG = -nFε⁰ 3. Equilibrium Constant: ε⁰ = (0.0592 / n) log K (at 298K) 4. Nernst Equation: ε = ε⁰ – (0.0592 / n) log Q 5. Charge Calculation: Q = I × t 6. Electrical Work: w = -nFε⁰ Legend for Constants and Units: ε⁰: Standard cell potential (V) n: Number of electrons transferred F: Faraday’s constant = 96485 C/mol R: Ideal gas constant = 8.314 J/(mol·K) T: Temperature in Kelvin Q: Reaction quotient (unitless) I: Current in amperes (A) t: Time in seconds (s)  w: Work in joules (J) Here's a polished version of your Study Guide: Materials Chemistry with improvements in organization, clarity, and formatting: Study Guide: Materials Chemistry Key Concepts to Master: 1. Types of Materials (5.45%) Metals: o Excellent electrical and thermal conductivity. o Malleable and ductile (e.g., copper, aluminum). Ceramics: o Brittle, heat-resistant, low electrical conductivity (e.g., porcelain, silicon carbide). Polymers: o Long-chain molecules with varied properties (e.g., plastics, rubber). Composites: o Combination of two or more materials to enhance properties (e.g., fiberglass). Nanomaterials: o Materials at the nanoscale (1-100 nm) with enhanced strength, conductivity, or reactivity. 2. Intermolecular Forces (3.63%) Ion-Dipole Interactions: o Electrostatic attraction between a charged ion and a polar molecule. Dipole-Dipole Forces: o Attraction between molecules with permanent dipoles. Hydrogen Bonding:  o Strong dipole-dipole interaction involving hydrogen with oxygen, nitrogen, or fluorine. London Dispersion Forces: o Weak forces caused by temporary dipoles in molecules. Ionic Forces: o Strong electrostatic attraction between oppositely charged ions in a lattice. 3. Crystalline Solids (3.63%) Types of Solids: o Ionic Solids: Strong electrostatic forces (e.g., NaCl). o Covalent Solids: Network solids with strong covalent bonds (e.g., diamond). o Metallic Solids: Sea of electrons enables conductivity (e.g., copper). o Molecular Solids: Held by intermolecular forces (e.g., ice). 4. Crystal Structures (1.82%) Crystal Lattices: o Regular 3D arrangement of atoms, ions, or molecules. Unit Cells: o Smallest repeating structure in a crystal lattice: ▪ Simple Cubic (SC): 1 atom/unit cell. ▪ Body-Centered Cubic (BCC): 2 atoms/unit cell. ▪ Face-Centered Cubic (FCC): 4 atoms/unit cell. Important Calculations: o Edge Length: Relates to atom radius: ▪ FCC: a=4r2a = \frac{4r}{\sqrt{2}}. ▪ BCC: a=4r3a = \frac{4r}{\sqrt{3}}. ▪ Simple Cubic: a=2ra = 2r. o Volume of Unit Cell: V=a3V = a^3.  o Density: Density=Mass of atoms in unit cellVolume of unit cell\text{Density} = \frac{\text{Mass of atoms in unit cell}}{\text{Volume of unit cell}}. o Mass of Atoms in Unit Cell: m=Number of atoms per unit cell×Molar MassNA,m = \frac{\text{Number of atoms per unit cell} \times \text{Molar Mass}}{N_A}, where NA=6.022×1023N_A = 6.022 \times 10^{23} atoms/mol (Avogadro's number). 5. Polymer Materials (5.45%) Types: o Thermoplastics: Re-moldable upon heating (e.g., polyethylene). o Thermosets: Harden permanently (e.g., epoxy resin). o Elastomers: Stretchable materials (e.g., rubber). Applications: o Packaging, textiles, construction. 6. Semiconductors (1.82%) Energy Band Theory: o Valence Band: Outermost electron energy levels. o Conduction Band: Higher energy levels where electrons move freely. o Band Gap: Determines material conductivity: ▪ Insulators: Large gap. ▪ Conductors: Overlapping bands. ▪ Semiconductors: Small gap (e.g., silicon). Doping: o N-Type: Extra electrons (e.g., phosphorus in silicon). o P-Type: Creates holes (e.g., boron in silicon). Important Concepts in Depth: Strength of Materials Tensile Strength: Resistance to elongation under tension.  Shear Strength: Resistance to forces causing sliding. Compressive Strength: Resistance to squeezing forces. Elasticity: Ability to return to the original shape after deformation. Hardness: Resistance to deformation (e.g., indentation, abrasion). Malleability: Ability to deform under compressive forces. Plasticity: Permanent deformation under applied forces. Phase Diagrams and Lever Rule Phase Diagrams: o Show the states of a substance at various temperatures and pressures. o Triple Point: Conditions where all three phases coexist. o Supercritical Fluid: Above critical temperature and pressure, indistinguishable between liquid and gas. Lever Rule: o Determines the composition of phases in a binary mixture: Mass fraction of phase 1=Distance to phase 2 boundaryTotal tie line length.\text {Mass fraction of phase 1} = \frac{\text{Distance to phase 2 boundary}}{\text{Total tie line length}}. Bragg’s Law and Light Interference in Crystals Diffraction: o Bending of waves as they encounter an obstacle. Bragg’s Law: o Relates X-ray wavelength, diffraction angle, and interplanar spacing: 2dsin⁡θ=nλ,2d \sin\theta = n\lambda, where: ▪ dd: Distance between adjacent planes in the crystal. ▪ θ\theta: Angle of incidence. ▪ λ\lambda: Wavelength of X-rays. ▪ nn: Order of diffraction. Applications:  o Used in X-ray crystallography to determine crystal structure. Composite Materials and Nanomaterials Composite Materials: o Combine properties of two materials for improved performance (e.g., carbon fiber). Nanomaterials: o High surface area-to-volume ratio. o Enhanced electrical, mechanical, and chemical properties. o Applications in medicine, electronics, and catalysis. To ensure that everything in the Environmental Chemistry section is covered comprehensively, let's break down the topics and provide a detailed summary. This will help you better understand and memorize the material for your test. Since Environmental Chemistry constitutes 14.54% of your exam, focusing on the key concepts and terminologies is crucial. Environmental Chemistry Summary 1. Terminologies (5.45%) Atmosphere: The layer of gases surrounding Earth, consisting primarily of nitrogen (78%) and oxygen (21%). Hydrosphere: All the water on Earth, including oceans, rivers, lakes, and groundwater. Lithosphere: The solid outer part of Earth, including the crust and upper mantle. Biosphere: The global ecological system that integrates all living organisms and their interactions. Pollution: The introduction of harmful substances or energy into the environment, causing negative impacts. Greenhouse Effect: The trapping of heat in the atmosphere by greenhouse gases (e.g., CO₂, CH₄, H₂O), leading to global warming. Eutrophication: The enrichment of water bodies with excess nutrients (e.g., nitrogen, phosphorus), resulting in excessive plant growth and oxygen depletion. Acid Rain: Rainwater with a pH lower than 5.7, caused by the dissolution of sulfur dioxide (SO₂) and nitrogen oxides (NOx) in the atmosphere.  Photochemical Smog: A type of air pollution formed by the interaction of sunlight with pollutants like NOx and volatile organic compounds (VOCs), resulting in harmful compounds such as ozone. 2. Pollution in Air, Water, and Soil (9.09%) Air Pollution: Primary Pollutants: Directly emitted into the atmosphere (e.g., CO, NOx, SO₂, particulate matter). Secondary Pollutants: Formed by chemical reactions in the atmosphere (e.g., ozone, PAN, nitric acid). Sources of Air Pollution: o Natural Sources: Volcanic eruptions, wildfires, dust storms. o Anthropogenic Sources: Vehicle emissions, industrial processes, burning of fossil fuels. Effects of Air Pollution: o Health Impacts: Respiratory diseases, cardiovascular issues, cancer. o Environmental Impacts: Acid rain, ozone depletion, global warming. Control Measures: o Use of catalytic converters in vehicles. o Implementation of emission standards. o Promotion of renewable energy sources. Water Pollution: Types of Water Pollutants: o Oxygen-Demanding Materials: Measured by BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand). o Nutrients: Nitrogen and phosphorus, leading to eutrophication. o Pathogens: Bacteria, viruses, and parasites from untreated sewage. o Heavy Metals: Toxic metals like lead (Pb), mercury (Hg), and cadmium (Cd). o Oil Spills: Harmful to aquatic life and ecosystems. Sources of Water Pollution: o Industrial discharge, agricultural runoff, sewage, oil spills.  Effects of Water Pollution: o Health Impacts: Waterborne diseases (e.g., cholera, typhoid). o Environmental Impacts: Death of aquatic organisms, loss of biodiversity. Control Measures: o Wastewater treatment plants. o Regulation of industrial discharge. o Public awareness campaigns. Soil Pollution: Sources of Soil Pollution: o Industrial Waste: Heavy metals, chemicals, and solvents. o Agricultural Activities: Pesticides, fertilizers, and irrigation with contaminated water. o Urbanization: Construction debris, improper waste disposal. Effects of Soil Pollution: o Health Impacts: Contaminated food and water, leading to diseases. o Environmental Impacts: Soil degradation, loss of fertility, harm to soil organisms. Control Measures: o Bioremediation: Using microorganisms to degrade pollutants. o Phytoremediation: Using plants to absorb and remove contaminants. o Soil Washing: Removing contaminants by washing the soil with water or solvents. Key Concepts to Memorize: 1. Air Pollution: Primary vs. Secondary Pollutants: Understand the difference and examples of each. Greenhouse Gases: CO₂, CH₄, H₂O, N₂O. Ozone Depletion: Caused by CFCs, leading to the formation of the ozone hole. Photochemical Smog: Formation process and key reactions (e.g., NO₂ + sunlight → NO + O·). 2. Water Pollution:  Eutrophication: Caused by excess nutrients (N, P), leading to algal blooms and oxygen depletion. BOD and COD: Understand how these measure water pollution. Heavy Metals: Know their sources and effects (e.g., Pb from leaded gasoline, Hg from industrial waste). 3. Soil Pollution: Sources: Industrial waste, pesticides, fertilizers. Effects: Soil degradation, loss of fertility, health risks. Remediation: Bioremediation, phytoremediation, soil washing. Memorization Techniques: 1. Active Recall: o Test yourself on key terms like "eutrophication," "photochemical smog," and "bioremediation" without looking at your notes. 2. Mnemonics: o For air pollutants: "CO NOx SOx" (Carbon Monoxide, Nitrogen Oxides, Sulfur Oxides). o For water pollutants: "BOD COD N P" (Biochemical Oxygen Demand, Chemical Oxygen Demand, Nitrogen, Phosphorus). 3. Visual Aids: o Draw diagrams of the hydrological cycle, nitrogen cycle, and ozone depletion process. 4. Chunking: o Break down the material into smaller sections (e.g., air pollution, water pollution, soil pollution) and study one section at a time. 5. Repetition: o Review the material multiple times, spacing out your study sessions to improve retention. Practice Questions: 1. Define the following terms: o Eutrophication  o Photochemical smog o Bioremediation 2. Explain the process of ozone depletion in the stratosphere. What are the main chemicals responsible for it? 3. What are the primary sources of water pollution, and how do they affect aquatic ecosystems? 4. Describe the effects of soil pollution on human health and the environment. What are some methods to remediate contaminated soil? 5. How does the greenhouse effect contribute to global warming? List the main greenhouse gases and their sources. Summary of Environmental Chemistry Topics: Topic Key Points Terminologies Atmosphere, hydrosphere, lithosphere, biosphere, pollution, greenhouse effect. Air Pollution Primary/secondary pollutants, ozone depletion, photochemical smog, acid rain. Water Pollution Eutrophication, BOD/COD, heavy metals, oil spills, wastewater treatment. Soil Pollution Industrial waste, pesticides, fertilizers, bioremediation, phytoremediation. 1. Importance of Chemical Safety (5.45%) Chemical safety is essential in engineering to ensure the safe handling, storage, and disposal of chemicals, protecting individuals, communities, and the environment from hazardous substances. Key points include: Accident Prevention: Proper safety measures reduce risks such as chemical spills, fires, and explosions. Health Protection: Minimizes exposure to toxic substances, preventing both short-term and long-term health effects. Environmental Protection: Prevents contamination of air, water, and soil, supporting sustainable practices. Regulatory Compliance: Adhering to safety standards and regulations (e.g., OSHA, GHS) is mandatory. Cultural Responsibility: Promotes a culture of safety within engineering practices. 2. NFPA and GHS Hazard Identification Systems (5.45%) 2.1. NFPA Hazard Identification System The National Fire Protection Association (NFPA) uses a color-coded diamond to communicate hazards: Blue (Health Hazard): 0 (No hazard) to 4 (Severe hazard). Red (Flammability): 0 (No hazard) to 4 (Extreme flammability). Yellow (Reactivity): 0 (Stable) to 4 (May detonate). White (Special Hazards): Indicates specific risks such as radioactivity, water reactivity, or oxidizing agents. Example: A chemical with a high flammability (Red: 4), moderate health hazard (Blue: 2), and low reactivity (Yellow: 1) would have the corresponding NFPA diamond ratings. 2.2. GHS Hazard Identification System The Globally Harmonized System (GHS) standardizes chemical hazard communication worldwide. Key elements include: Pictograms: Visual symbols representing hazards (e.g., flame for flammability, skull and crossbones for toxicity). Signal Words: "Danger" (severe hazard) or "Warning" (less severe hazard). Hazard Statements: Standardized phrases describing the nature of the hazard (e.g., "Causes severe skin burns"). Precautionary Statements: Safety measures to minimize risks (e.g., "Wear protective gloves"). Example: A GHS label for sulfuric acid might include: Pictogram: Corrosion. Signal Word: Danger. Hazard Statement: Causes severe skin burns and eye damage. Precautionary Statement: Wear protective gloves and eye protection. 3. Hazard Classifications Hazards are classified into various categories: 1. Physical Hazards: Risks like slippery floors, poor lighting, or excessive noise.  2. Chemical Hazards: Substances such as gases, fumes, or liquids that can cause harm upon exposure. 3. Ergonomic Hazards: Poor workstation design or repetitive movements that affect the musculoskeletal system. 4. Radiation Hazards: Exposure to electromagnetic waves like X-rays or UV rays. 5. Psychological Hazards: Stress, workload, or discrimination affecting mental health. 6. Biological Hazards: Exposure to viruses, bacteria, or other biological agents. 4. Hazardous Substances A hazardous substance is any chemical that poses a physical or health risk. According to OSHA, these substances are classified into: Physical Hazards: Flammable, explosive, or reactive chemicals. Health Hazards: Chemicals causing acute (short-term) or chronic (long-term) health effects. Example: Hydrochloric acid is hazardous due to its corrosive nature (physical hazard) and its potential to cause respiratory issues (health hazard). 5. Safety Data Sheets (SDS) SDS provides detailed information on chemical substances, including: 1. Identification: Product name and supplier details. 2. Hazard Identification: GHS classification, pictograms, and hazard statements. 3. Composition: Chemical ingredients and their concentrations. 4. First Aid Measures: Steps to take in case of exposure. 5. Firefighting Measures: Suitable extinguishing methods. 6. Accidental Release Measures: Procedures for cleanup. 7. Handling and Storage: Safe practices for chemical handling and storage. 8. Exposure Controls: Protective measures and engineering controls. 9. Physical/Chemical Properties: Boiling point, flammability, etc. 10. Stability and Reactivity: Conditions to avoid and incompatible materials. 11. Toxicological Information: Health effects and toxicity data.  12. Ecological Information: Environmental impact. 13. Disposal Considerations: Waste disposal recommendations. 14. Transport Information: Shipping guidelines. 15. Regulatory Information: Compliance with safety regulations. 16. Other Information: Additional safety details. 6. Hierarchy of Hazard Controls The hierarchy of hazard controls prioritizes measures to reduce risks: 1. Elimination: Completely remove the hazard. 2. Substitution: Replace hazardous substances with safer alternatives. 3. Engineering Controls: Isolate people from hazards (e.g., using ventilation systems). 4. Administrative Controls: Implement safety policies and provide training. 5. Personal Protective Equipment (PPE): Use gloves, goggles, or respirators when other measures are not sufficient. 7. Personal Protective Equipment (PPE) PPE is essential for protecting individuals from chemical hazards: Gloves: Protect hands from corrosive substances. Goggles: Protect eyes from splashes or fumes. Respirators: Prevent inhalation of toxic gases. Lab Coats: Protect skin and clothing from chemical spills. 8. Emergency Preparedness Emergency Plans: Develop and rehearse response plans for chemical spills, fires, or exposure incidents. First Aid Training: Ensure personnel are trained to respond to chemical injuries. Spill Kits: Keep spill kits available for quick cleanup. 9. Key Definitions  Hazard: A potential source of harm (e.g., a toxic chemical). Risk: The likelihood and severity of harm occurring (e.g., the chance of exposure to a toxic chemical).