Lesson-4-Atomic-Mass-Empirical-Formula-and-Molecular-Formula

Page 1: Title and Instructor

• Institution: Gardner College

• Course: General Chemistry 1

• Instructor: Mr. Sherwin Sinajonon

Page 2: Learning Objectives

• Relative Atomic Mass: Explain the concept and significance.

• Avogadro’s Number: Illustrate with examples.

• Molar Mass: Determine for elements and compounds.

• Mass Calculation: Calculate mass for a given number of moles of an element (and vice versa).

Page 3: Continuing Objectives

• Percent Composition: Calculate from the formula of a compound.

• Empirical Formula: Derive from the percent composition.

• Molecular Formula: Calculate using the molar mass.

Page 4: Understanding Atomic Mass

• Definition: Mass of a single atom expressed in atomic mass units (amu).

• Atomic Mass Unit: Defined as 1/12 of a carbon-12 atom's mass, equating to about 1.66 × 10^(-27) kg.

• Use in Chemistry: Important for understanding atomic and molecular scale behaviors.

Page 5: More on Atomic Mass

• Atomic Mass vs. Weight: Often called atomic weight, it refers to the mass of an atom in amu.

• Isotopes: Different forms of the same element with varying weights; example: Hydrogen has isotopes Deuterium and Tritium.

Page 6: Hydrogen Isotopes

• Abundance of Isotopes:

  • 1H: 99.985%

  • 2H: 0.015%

• Visual Representation: Depiction of hydrogen isotopes, their protons (P), and neutrons (N).

Page 7: Isotopic Mass of Hydrogen

• Mass of Isotopes:

  • 1H = 1.00784 amu

  • 2H = 2.01410 amu

• Average Mass: Average of the isotopes is calculated as 1.51097 amu.

Page 8: Isotopic Mass and Abundance Table

• List of Elements:

  • Helium: 3.016029 amu (0.000137%) and 4.002603 amu (99.999863%)

  • Lithium, Carbon, Sulfur, Chlorine, Potassium: Isotopic masses and their corresponding abundances provided.

Page 9: Chlorine Isotopes Analysis

• Chlorine Isotopes:

  • 36Cl: 34.968853 amu (75.78%)

  • 37Cl: 36.965903 amu (24.22%)

• Objective: Determine relative atomic mass.

Page 10: Calculating Relative Atomic Mass

• Steps:

  1. Convert percent abundance to decimals (divide by 100).

  2. Multiply atomic mass of isotopes by abundance.

  3. Sum these products for the final relative atomic mass.

Page 11: Example for Chlorine Relative Atomic Mass

• Reiteration of Isotope Details:

  • Confirm isotopes and abundance for clarity.

Page 12: Chlorine Isotope Summary

• Isotopes and Their Properties Re-emphasized: Details of isotopes and material previously covered.

Page 13: Calculation of Chlorine's Relative Atomic Mass

• Computation Steps:

  • 26.499396 + 8.9531417 = 35.4525377 amu

• Final Rounded Value: 35.45254 amu

Page 14: Lithium Isotopes Overview

• Isotope Detail for Lithium:

  • 6Li: 6.015122 amu (7.59%)

  • 7Li: 7.016004 amu (92.41%)

Page 15: Calculation of Lithium’s Relative Atomic Mass

• Detailed Steps:

  • Calculation breakdown for both isotopes provided for accuracy.

Page 16: Final Calculation for Lithium

• Summed Result for Relative Atomic Mass:

  • From calculations: 6.9400370562 amu

Page 17: Definition of Formula Weight

• Formula Weight: Summation of atomic weights of atoms in a compound.

• Example with HCl: Calculation breakdown shared for HCl demonstrating method for finding formulation.

Page 18: Ca3(PO4)2 Formula Weight Calculation

• Step-by-step computation example: Individual atomic weights for K, Mn, and O calculated leading to overall weight of the compound.

Page 19: H2O Formula Weight Calculation

• Detailed atomic weight segmentation: For water involving individual contributions of H and O.

Page 20: Ca3(PO4)2 Continued Calculation

• Heavy focus on detailed calculations: Steps traced out for clear understanding of molecular mass assessment.

Page 21: Explaining Molar Mass

• Definition: Molar mass intrinsic to one mole of substance, presented in grams/mole.

• Foundational relation to formula weight emphasized.

Page 22: Molar Mass in Context

• Weight vs Molar Mass examples: Transition of amu values to gram values explained through examples with H2O and Ca3(PO4)2.

Page 23: Introduction to Avogadro's Number

• Definition: Number of units (atoms, molecules, etc.) in one mole equals 6.022 x 10^23.

• Importance in Stoichiometry touched upon.

Page 24: Units of Measurement in Avogadro's Number

• Explanation of Units: Identifies the types of measurable units involved with Avogadro's number across different chemical contexts.

Page 25: Avogadro’s Number Calculation Example

• Sample Table: Showcases various mole amounts for sodium atoms alongside corresponding weights and atom counts.

Page 26: Example Calculation with Molar Mass of NaOH

• Contextual Problem: Compute moles of NaOH based on a given mass, tools for calculation indicated.

Page 27: Calculation Resolution of NaOH Moles

• Explicit Steps Provided: Conversion from weight to mole values explained in a straightforward manner demonstrating successful computation.

Page 28: Ca3(PO4)2 Weight Calculation Problem

• Given Data: Clearly stated values to compute the necessary mass of a specific mole amount provided for practice.

Page 29: Ca3(PO4)2 Calculation Solution

• Problem Solving: Weight of substance calculated from number of moles reaffirms understanding of mole to gram conversions.

Page 30: CO2 Mole Calculation Introduction

• Problem Statement: Weight given, molar mass specified, understanding of mole calculations primed for computation.

Page 31: Solving for Moles in CO2 Context

• Mole Calculation Breakdown: Clear and direct computation leads to the mole amount derived from the weight provided.

Page 32: Molecule Calculation from Molar Data

• Utilization of Avogadro's Number: Using the derived moles to calculate the total number of molecules in a given mass.

Page 33: Percent Composition Introduction

• Definition and Importance: Understanding the percent composition allows insights into the makeup of compounds via mass comparisons.

Page 34: Percent Composition Formula

• Mathematical Definition: Presentation of formulaic representation for calculating percent composition with examples.

Page 35: Water Percent Composition Calculation Example

• Exploration of H2O: Stepwise approach to finding out the percent composition of elements in water underlined.

Page 36: Percent Composition Table

• Visual Data Presentation: Further examples looking into percent compositions paving way for comprehensive understanding.

Page 37: Percent Composition for Ca(NO3)2

• In-depth Calculation Steps: Each element's data presented distinctly illustrating contribution to total composition.

Page 38: Percent Composition Summary of Ca(NO3)2

• Final Recap of Percentages: Clear summation of resulting percentages from earlier calculations emphasizing mastery of topic.

Page 39: Empirical vs. Molecular Formula Definition

• Contrast Highlighted: Empirical formula as simplest atom ratio illustrated alongside molecular formula representing actual atom counts.

Page 40: Example Calculation for Empirical Formula

• Hypothetical Scenario: Composition outlined for further analysis towards derivation of empirical formula.

Page 41: Steps to Find Empirical Formula

• Step-by-step approach: Focus on deriving mole counts from a simplified sample value defined.

Page 42: Calculating Moles of Compound Elements

• Mole Calculations Detailed: Introduction of molar conversions for all constituent elements.

Page 43: Mole Calculations Continued

• Molar Findings: Final moles figure clarified reinforcing earlier format.

Page 44: Steps for Building Empirical Formula

• Dividing the smallest number of moles: Crucial steps detailed explaining simplification process.

Page 45: Empirical Formula Resolution Steps

• Substituting for Smallest Quotients: Clear directives supporting methodology on achieving empirical formula successfully outlined.

Page 46: Completing Empirical Formula Steps

• Final Formula Construction: Ensuring incorporation of whole number ratios in final implications.

Page 47: Determining Molecular Formula Steps

• Methodology Outlined: Key procedures for reaching molecular formula shared.

Page 48: Empirical and Molecular Formula Example Problem

• Heuristic Breakdown: Compound characteristics outlined for computational practice.

Page 49: Empirical Formula Weight Calculation

• Molarity Figures Provided: Individual contributions from each elemental composition aligned for computation.

Page 50: Simplifying Mole Ratios for Empirical Formula

• Final Ratios Established: Final forms of elements derived fulfilling empirical expectations.

Page 51: Compilation of Empirical Formula Weight

• Weight Compilation Approach: Each computation focused upon to formulate a coherent final weight.

Page 52: Derivation of Molecular Formula from Weight

• Finding the Multiple: Important variable representations established along the path to final formula.

Page 53: Final Molecular Formula Presentation

• Finalizing Chemical Formulation: Conclusively pointing towards the derived molecular structure.

Page 54: Additional Empirical Formula Problems

• Problem Presentations: Assigned tasks around percentage rules and molar conversions to drive understanding.

Page 55: Sulfur and Iron Compound Problem

• Complexity Building: Challenge-oriented task setup for deeper exploration of empiricals.

Page 56: Compound Including Potassium and Oxygen

• Diversity in Element Examples: Purpose of this exercise teaches varied approaches in empirical formula deductions.

Page 57: Phosphorus and Oxygen Ratio Formula Exploration

• Focused Chemical Investigation: Reliable problems designed to foster skill-building in related applications.

Page 58: Empirical Formula Reinforcement

• Finalized Hydrocarbon Example: Calculative tasks lead right back into empirical formulations for completion.

Page 59: Summary of Key Points (Part 1)

• Atomic Mass Unit Importance: Defined basis for unified measuring system across atomic levels.

• Relative Atomic Mass Methodology: Stepwise directives revisited to ensure foundational knowledge retention established.

Page 60: Summary of Key Points (Part 2)

• Formula Weight Understanding: Core elements of formulas leading to weight aggregations clarified in sync with molecular principles.

Page 61: Summary of Key Points (Part 3)

• Emphasis on Molar Mass: Integral connections between formula weight to practical gram representations.

• Avogadro’s Number Utility: Continues to reign as fundamental in quantitative chemistry analysis.

Page 62: Summary of Key Points (Part 4)

• Percent Composition Overview: Central to chemical mixtures and foundational understanding solidified.

Page 63: Summary of Key Points (Part 5)

• Final Contrast of Empirical and Molecular Formula: Distinction between formulaic representations made clear across various topics.

Page 64: References (Part 1)

• Citing educational materials and resources utilized for gathering informational content.

Page 65: References (Part 2)

• Further details on resources and references listed to support document's educational integrity across topics.