G9.Acidbasessalts_ppt

PROMETHEUS SCHOOL

• Learning Reimagined

• MYP Year-4

• Acids, Bases and Salts

  • Made by Ms. Aakansha Mahajan

Contact

• For doubts: aakansha.mahajan@prometheusschool.com

Learning Objectives

• Understand characteristics of acids and bases.

• Explore Arrhenius, Bronsted-Lowry, and Lewis concepts.

• Learn chemical reactions involving acids and bases.

• Understand pH value and types of indicators (natural, synthetic, universal).

• Differentiate between strengths of acids and bases.

• Recognize dilute vs. concentrated acids and bases.

• Discuss oxides and their types.

• Understand types and preparation of salts:

  • Soluble (e.g., copper sulphate)

  • Insoluble (e.g., lead iodide)

Table of Contents

• Unit details

• Statement of Inquiry, Key Concepts, Related Concepts, Inquiry Questions

• Introduction to acids and bases

• Arrhenius and Bronsted-Lowry concepts

• Chemical reactions of acids and bases

• Salts and their preparation

• Oxides and their types

Unit Overview

• Statement of Inquiry: Properties of acids and bases determine their use and function.

• Key Concept: System

• Related Concepts: Function, Evidence

• Global Context: Identities and Relationships

• Inquiry Questions:

  • Factual: What are the chemical properties of acids and bases?

  • Conceptual: How do acids and bases behave in different situations and conditions?

  • Debatable: What is the fairest way to use our chemical resources?

Physical Properties of Acids and Bases

Acids

• Corrosive and can corrode/break down substances

• pH below 7

• Taste sour (found in fruits/juices)

• Good electrical conductors

Bases

• Also corrosive

• pH above 7 (7 is neutral)

• Taste bitter (found in soaps)

• Slippery texture

• Also good conductors of electricity

Arrhenius Concept of Acids and Bases

• Defined by chemist Svante Arrhenius:

  • Acids: substances that dissociate in water to produce H+ ions

  • Bases: substances that dissociate in water to produce OH- ions

  Examples:

  • NaOH(aq) → Na+(aq) + OH-(aq) (Base)

  • HCl(aq) → H+(aq) + Cl-(aq) (Acid)

Indicators

Nature of Indicators

• Indicators signal changes, showing whether a substance is acid, base, or neutral, often through color change.

Types of Indicators

• Natural Indicators:

  • Red cabbage, bougainvillea, red onion.

• Artificial Indicators:

  • Methyl orange, methyl red, bromothymol blue, phenolphthalein, litmus, universal indicator.

Strength of Acids and Bases

• Understanding pH scale.

• Differences in strength (strong vs. weak acids/bases).

Neutralization Reaction

• General formula: Acid + Base → Water + Salt

• Example: HCl + NaOH → H2O + NaCl

Reactions of Acids

• Metals with acids produce salts and hydrogen. (e.g., Mg + HCl → MgCl2 + H2)

• Metal oxides plus acids yield salts and water. (e.g., MgO + HCl → MgCl2 + H2O)

• Metal carbonates plus acids generate salts, water, and carbon dioxide.

Types of Oxides

• Basic Oxides: React with water/acids to form salts.

• Acidic Oxides: Usually gases, react with bases to form salts.

• Amphoteric Oxides: Can act as either acids or bases.

• Neutral Oxides: Do not react with acids or bases.

Salts: Definition and Types

• Salts are ionic compounds produced from the reaction of acids and bases.

• Types include soluble (e.g., sodium hydroxide) and insoluble (e.g., lead chloride).

Preparation of Salts

1. Reaction with Metals:

   • Suitable for reactive metals (above hydrogen in the reactivity series).

   • Example (zinc sulfate): Zn + H2SO4 → ZnSO4 + H2

2. From Insoluble Bases:

   • Example (copper sulfate): CuO + H2SO4 → CuSO4 + H2O

3. Using Precipitation Reactions:

   • Mixing soluble salts to produce insoluble precipitates.

   • E.g., Pb(NO3)2 + NaCl → PbCl2 + NaNO3

Solubility Rules

Soluble

• All group I elements and nitrates.

Insoluble

• Most hydroxides and carbonates.

Summary of Salts Preparation Steps

• Identify ions, use solubility rules, mix solutions, filter the precipitate, wash and dry.