Lecture Notes

Introduction

• Importance of subscribing to channels for updates
• Apps for educational content (e.g., फटाफट Android app)
• Mention of modern scientists and various subscriptions for resources

Mixtures and Solutions

Homogeneous Mixtures

• Mixtures with uniform composition
• Examples: Blood
• Characteristics: Particles are well-distributed and uniform
• Visuals: Particles not visible to naked eye, stable composition

Heterogeneous Mixtures

• Mixtures with non-uniform composition
• Identification: Clearly visible different parts
• Examples: Sand and iron filings

Solutions

Definition

• Homogeneous mixture of two or more substances
• Consists of solute and solvent
• Examples: Saltwater, sugar in water

Properties

• Homogeneous at molecular level
• Particles are too small to be seen
• Components don’t separate on standing

Solute and Solvent

• Solute: Substance dissolved (smaller quantity)
• Solvent: Substance in which solute is dissolved (larger quantity)

Concentration of Solutions

Definition

• Amount of solute present in a given amount of solvent or solution

Methods of Expressing Concentration

• Percentage (by mass or volume)
• Molarity (moles of solute per liter of solution)

Types of Solutions

Based on Solvent

• Solid in Liquid (salt in water)
• Liquid in Liquid (alcohol in water)

Based on Saturation

• Unsaturated: Contains less solute than it can hold
• Saturated: Maximum amount of solute at a given temperature
• Supersaturated: More solute than normally possible (unstable)

Methods of Separation

Filtration

• Separates solid particles from liquids

Distillation

• Separates based on boiling points

Crystallization

• Formation of pure solid particles from a solution

Elements and Compounds

Elements

• Pure substances that cannot be broken down
• Composed of one type of atom
• Examples: Oxygen (O), Hydrogen (H)
• Classified as metals, non-metals, metalloids

Compounds

• Formed from two or more elements chemically combined
• Have unique properties different from constituent elements
• Examples: Water (H2O), Carbon Dioxide (CO2)

Properties of Metals and Non-Metals

Metals

• Good conductors of heat and electricity
• Malleable, ductile
• Examples: Gold, Silver, Copper

Non-Metals

• Poor conductors of heat and electricity
• Brittle, non-ductile
• Examples: Sulfur, Neon

Metalloids

• Properties intermediate between metals and non-metals
• Examples: Silicon, Germanium