Chapter_7

Introduction

  • Chapter 7: Chemical Quantities and Reactions

  • Focuses on the calculation of moles, balancing equations, and classification of reactions.

  • Relevance to disciplines such as exercise physiology and chronic disease management.

Chapter Objectives

  • Molar Mass Calculations

    • Determine the molar mass from formulas.

    • Convert between grams and moles using the molar mass as a factor.

  • Mole Conversions

    • Use Avogadro's number for conversions between moles and particles.

  • Changes in Matter

    • Classify changes as chemical or physical.

  • Chemical Equation Analysis

    • Balance chemical equations.

    • Classify equations: combination, decomposition, single-displacement, double-replacement, combustion.

  • Redox Reactions

    • Understand oxidation and reduction in reactions.

Key Math Skills Required

  • Percentage Calculations

  • Equation Solving

  • Scientific Notation

Core Chemistry Skills

  • Significant figures counting and usage in calculations.

  • Writing and using conversion factors for equalities.

  • Writing and naming ionic and molecular compounds.

The Mole Concept

  • Definition of a Mole

    • A counting term or unit defined as 6.02 × 10^23 particles (Avogadro's number).

    • Equivalent to counting terms like dozen, case, etc.

  • Moles of Atoms

    • 1 mole of an element contains 6.02 × 10^23 atoms (e.g., Carbon, Sodium).

Conversion Factors Related to Moles

  • Avogadro’s Number

    • 1 mole = 6.02 × 10^23 particles.

  • Important for converting between moles and quantities of atoms or molecules.

Molar Mass Calculations

  • Definition

    • The molar mass is the mass of 1 mole of an element or compound, equal to its atomic or molecular weight in grams.

  • Example: Sodium (Na) has a molar mass of 22.99 g/mol.

  • Calculating Molar Mass

    • Multiply the molar mass of each element by its subscript in the formula.

    • Example Calculation: Molar mass of Lithium Carbonate (Li2CO3) = (2 x Li) + (1 x C) + (3 x O).

Chemical Reactions

  • Types of Chemical Reactions

    • Combination Reactions: Two or more elements combine to form one product.

      • Examples: 2Mg + O2 -> 2MgO.

    • Decomposition Reactions: One substance splits into two or more simpler substances.

      • Example: 2HgO -> 2Hg + O2.

    • Single Replacement Reactions: One element replaces a different element in another compound.

      • Example: Zn + 2HCl -> ZnCl2 + H2.

    • Double Replacement Reactions: The positive ions of two compounds exchange places.

      • Example: AgNO3 + NaCl -> AgCl + NaNO3.

    • Combustion Reactions: A carbon compound burns in oxygen to produce CO2 and H2O.

      • Example: CH4 + 2O2 -> CO2 + 2H2O + energy.

Oxidation-Reduction Reactions

  • Defining Redox Chemistry

    • Oxidation involves the loss of electrons; reduction involves the gain of electrons.

    • Example: Rust formation (4Fe + 3O2 -> 2Fe2O3).

Law of Conservation of Mass

  • Matter cannot be created or destroyed in chemical reactions.

  • Mass of products = mass of reactants; important for balancing chemical equations.

Summary of Reaction Types

  • Recognize and classify reaction types based on their characteristics and the exchange of ions/electrons.

  • Be able to balance equations by ensuring the number of atoms for each element is equal on both sides of the equation.