Chemistry Class Quiz: Mixtures and Reactions

Module 1: General Chemistry

• Chemistry is the study of matter
• Matter is anything that occupies space and has mass
• Mass refers to the amount of matter present in a material or object

Classification of Matter

• Element - simplest form, one component
• Compound - two or more elements (chemically combined)
• Mixture - two or more substances (not chemically combined)

States of Matter

• Solid: Definite shape and size, definite volume, vibration
• Liquid: Indefinite shape, definite volume (assumes the shape of the container), gliding motion
• Gas: Indefinite shape and volume, constant random motion

Units of Measurement

• Length - Meter (m)
• Mass - Kilograms (kg)
• Time - Seconds (sec)
• Temperature - Kelvin (K)

Classification of Mixtures

• Homogeneous: One phase (e.g., solutions)
• Heterogeneous: Two or more phases (e.g., suspensions, colloids)
  • Solution: uniform mixture (solute + solvent)
  • Suspension: coarse mixture (finely divided solid materials dispersed in a liquid)
  • Colloid: particle of solute not broken down to the size of molecules

Process of Separating Components of Mixtures

• Decantation - difference in specific gravity/density
• Distillation - evaporation and condensation
• Evaporation - separation by evaporation
• Magnetic Separation
• Filtration

Continuation of Mixture Separation Process

• Sorting
• Centrifugation - speed up the setting process of a precipitate
• Fractional Crystallization - lowering the temperature to separate based on differences in solute affinity
• Chromatography - separating based on differences in solute affinity

Properties of Matter

• Intrinsic: Intensive property, independent of mass/amount (e.g., density, specific gravity, melting point, viscosity, temperature, color)
• Extrinsic: Extensive property, dependent on mass (e.g., weight, volume, pressure, heat content, length, mass/cot, entropy, enthalpy, electrical resistance)

Changes that Matter Undergoes

• Physical Change: Change in phase (e.g., sublimation, deposition)
• Chemical Change: Change in both intrinsic and extrinsic properties (e.g., evolution of gas, formation of precipitate, emission of light, generation of electricity, production of mechanical energy, absorption/liberation of heat)

Types of Chemical Reactions

• Combination/Synthesis - A + B → AB
• Decomposition/Analysis - AB → A + B
• Single Displacement/Single Replacement - AB + C → AC + B
• Double Displacement - AB + CD → AC + BD
  • Neutralization: Acid + Base → Salt + Water

Processes Involved in Chemical Change

• Oxidation - + oxygen
• Reduction - oxygen or + hydrogen
• Neutralization - Acid + Base → Salt + Water
• Hydrolysis - Water + Salt → Acid + Base
• Saponification - Alkali + Fat → Soap + Glycerol
• Fermentation - Organic substances + Microbes → Alcohol

Nuclear Change

• Nuclear Fission - splitting of a heavy atom
• Nuclear Fusion - union of two light atoms to form a bigger molecule

Atomic Structure

• Protons = electrons = atomic number
• Neutrons= mass number - atomic number
• Electrons= protons - charge
• Mass number = protons + neutrons

General Principles in Electron Configuration

• Pauli's Exclusion Principle - no two electron shall have the same set of quantum numbers. Each atomic orbital can only accommodate 2 electrons.
• Heisenberg's Uncertainty Principle - impossible to simultaneously determine the electron momentum and position.
• Aufbau's Building Up Principle - lower energy levels are filled up first.
• Hund's Rule of Maximum Multiplicity - orbitals are filled singly before pairing up.

Fundamental Chemistry Laws

• Law of Conservation of Mass/Matter - Mass/Matter cannot be created or destroyed
• Law of Definite/Constant Proportions - Chemical compounds always contain the exact proportion of elements in fixed ratios by mass
• Law of Multiple Proportions
• Law of combining weights

Useful Trivias SA Board Exam

• 3 most abundant elements - O, Si, Al
• 1st element produced artificially - Tc= technetos
• Rarest element - At = Astatin
• Liquid at room temperature - Hg/Br

The Periodic Table of Elements

• (Provides a table of elements with organization by properties)

Family A & B Elements

• Family A: Representative elements arranged in the S and P blocks
• Family B: Transition Elements arranged in the D and F Blocks
  • D block - Transition metals
  • F block - Lanthanides/Actinides

Periodic Trends

• Atomic Radius
• lonization Energy
• Electron Affinity
• Nonmetallic character
• Metallic Character

Kinematic Molecular Theory

• Explains the phases of matter based on the movement of molecules/ions/atoms
  • Solid
  • Liquid
  • Gas

Solutions

• Homogeneous mixture of two or more substances (single phase)
  • Saturated- maximum solute
  • Unsaturated - less solute
  • Supersaturated - more solute than solvent

Factors Affecting Solubility

• Nature of Solute and Solvent ("like dissolves like")
• Temperature
  • Exothermic - solubility decreases with increasing temperature
  • Endothermic - solubility increases with increasing temperature
• Pressure (for gases only) - solubility increases with increasing pressure
• Particle Size/Surface Area - increased surface area leads to increased solubility
• Presence of Salts (salting out/ in)- presence of salt decreases/increases solubility with common ion effect

Forces of Attraction

• Intramolecular Forces (within molecules)
  • Ionic - electron transfer
  • Covalent - electron sharing (polar/nonpolar)
• Intermolecular Forces (between molecules)
• Van der Waals forces
  • Keesom - dipole-dipole
  • Debye - dipole-induced dipole
  • London Dispersion Forces- induced dipole-induced dipole
  • Ion-dipole
  • Hydrogen Bond

Physical Properties of Systems

• Additive Property- depends on the sum (molecular weight)
• Constitutive Property- depends on type/arrangement (optical rotation)
• Colligative Property- depends on the number of solute particles (e.g., vapor pressure lowering, boiling point elevation, freezing point depression. osmotic pressure)

Colligative Properties

• Vapor Pressure Lowering
• Boiling Point Elevation
• Freezing Point Depression
• Osmotic Pressure

Gas Laws

• Boyle's/Mariotte Law - P1V1 = P2V2
• Charles Law - V1/T1 = V2/T2
• Gay-Lussac's Law - P1/T1 = P2/T2
• Combined Gas Law - P1V1/T1 = P2V2/T2
• Ideal Gas Law
• Avogadro's Law - V1/n1 = V2/n2
• Dalton's Law of Partial Pressures - Pt = P1 + P2 + P3
• Graham's Law - Rate diffusion = 1/(square root of density)
• Fick's 1st Law

Acids and Bases

• Electrolytes (good conductors)
  • Strong electrolytes
  • Weak electrolytes
• Non-Electrolytes (do not conduct electricity)
• Acid-Base Theories (Arrhenius, Bronsted-Lowry, Lewis, Pearson's HSAB)
• Acids (taste sour. pH<7, turn litmus paper red)
• Bases (taste bitter, pH>7, turn litmus paper blue)
• Acid-Base Concepts (Pearson's HSAB)

Buffers

• Resist pH changes when acids or bases are added
• Consist of a weak acid and its conjugate base or weak base and its conjugate acid
• Henderson-Hasselbalch Equation
• Buffer Capacity

Thermochemistry

• Heat (q) - energy transfer due to temperature difference
• Work (w) - energy transfer between a system and its surroundings (compression/expansion of gas)
• Internal Energy (U)
• Enthalpy (H) - energy of a reaction
• Entropy (S) - degree of disorderliness
• Heat Capacity (c)
• Specific Heat
• Endothermic - absorbs heat, positive heat value
• Exothermic - releases heat, negative heat value
• Thermodynamically Spontaneous reactions: -H and +S; otherwise -H and -S
• Le Chatelier's Principle - a system in equilibrium will shift to relieve stress

Test your knowledge of fundamental chemistry concepts, including the properties of mixtures, physical and chemical changes, and the classification of reactions. This quiz covers essential topics such as saponification, solubility, and the characteristics of elements and compounds.