ASK THE CAT
  • Ask
  • FAQ
  • Summer 2020 Tutoring
    • Pre-Algebra Sessions >
      • :: Basic Division
      • :: Complex Division
      • :: Estimation Division
      • :: Division Practice Problems
    • Algebra II >
      • :: Cubic Equations
      • :: Complex Numbers
    • Chemistry >
      • Molarity Basics
    • C++ Sessions >
      • :: Introduction
      • :: Style v Syntax
      • :: Variables & Data Types
      • :: Intialize/Declare Variables
      • :: Types of Operators
      • :: Strings and Input - Output
      • :: How to Construct Arrays
  • AP Bio
    • :: Sketch Notes >
      • :: Part 1
      • :: Part 2
    • :: Chi-Squared Tests
    • :: Cancer
    • :: Hox Genes
    • :: Hardy-Weinberg Principle
    • :: Rule of Multiplication + Addition for Punnett Squares
    • :: CRISPR
    • :: Amino Acid
    • :: Peptide
    • :: Why study Peptides
    • :: Aquaporins
    • :: Gram Stains
    • :: Graph on Excel for Bio Lab
  • AP Chem
    • Organic Chemistry
    • I. Properties of Matter >
      • Neutralization
    • II. Periodic table >
      • Org of Periodic Table
      • :: Groups
    • III. Chemical bonding >
      • :: Mass to Mass conversion
      • :: Naming Acids
      • :: Cross Drop Charge
      • :: Predicting Products
      • :: Balance Equation Question
      • :: Learn to Balance Equation
      • :: VSEPR Simulation
    • IV. Molar Mass >
      • ::LR ER and excess reatant
      • :: Molecular/Formula Mass
      • :: Empirical Formula & Molar Mass
      • :: Percentages & Empirical Formula
      • :: Empirical formula
    • IV. Solutions and Solubility >
      • :: Types of Solutions with Solubility Curves
      • :: Solubility Curve
    • V. Easy Tricks and Tips >
      • :: Tip to Molecular Shapes
      • Memorizing Bond Angles and Polarity
      • :: Chemistry Formulas
      • :: Trick Polyatomic ions
    • VI. General AP Concepts >
      • :: Potential Energy Diagrams
      • :: Haber-Bosch
      • :: Le Chatelier
      • :: Pressure & Moles
      • ::Rydberg's Constant vs Unit of Energy
      • :: Equilibrium and RICE Tables
      • :: Kinetics
      • Galvanic Cells
    • :: Flash cards
    • :: VSEPR
  • AP Stats
    • Chi-Squared Tests
    • Applications of Statistics
    • Standardized Scores
    • Distributions Transformations
  • AP Calc
    • DI Method - Tabular Integration
    • Polar Curves: Tangent Line and Slope
    • Riemann Sums: Left and Right Approximations
    • :: Conic Sections Flash cards
    • :: Parent Functions Flash cards
    • Worked Out Problems >
      • :: Worked Out Problems I
      • :: Worked Out Problems II
      • :: Worked Out Problems III
      • :: Worked Out Problems IV
      • :: Worked Out Problems V
      • :: Worked Out Problems VI
      • :: Worked Out Problems VII
      • :: Worked Out Problems VIII
      • :: Worked Out Problems IX
      • :: Worked Out Problems X
      • :: Worked Out Problems XI
      • :: Worked Out Problems XII
      • :: Worked Out Problems XIII
    • Applying Trig Identities
    • L'Hopital's Rule
    • Differences Between Conic Sections
    • Graphing Conic Sections
    • :: Pre-Calc - Trig Identities
    • Tangent & Normal Lines
    • Indefinite integrals: U Sub
    • Calculus Derivatives >
      • Product Rule
      • Quotient Rule
      • Chain Rule
  • AP CS A
    • Studying for AP CSA 2020
    • :: Control Structures
    • :: What is Networking
    • :: Recursion
    • :: While Do While Loops in Java
    • :: Interface in Java
    • :: ArrayLists
    • :: Java Naming Conventions
    • :: Logic Circuits
    • :: Getters and Setters
    • :: Binary & Hexadecimal
  • AP Español
    • AP Español Salsa
  • Arduino
    • Quick Look
    • Project #1: Blinking LED
    • Project #2: Button LED
    • Project #3: Flowing LED
    • Project #4: LCD Display
    • Project #5: Serial Monitor
  • App
    • AP Go Pow How?
    • AP Go Pow APP Page
  • Musings
    • :: Backward induction
    • :: what is ISS
    • :: Rotational Matrices
    • :: Primary v Secondary Pollutants
    • :: Black Hole
    • :: Covid-19 Hackathon
    • :: Evolution of Immunizations
    • :: Predictions of Diseases
    • :: Book List
    • :: Patterncount
    • :: Binary Classification
    • :: Cybersecurity
    • :: Self Similarity
    • :: Trig Identities
    • :: UIL Number S
    • :: Box Offensive Play
    • :: Why Card Trick Works
    • :: Easy Multiplication
  • AP CREDIT
  • About

8th grade chemistry:  IV.  molar mass: Empirical formula

Picture








Molecules consist of two or more atoms bonded to one another through "covalent" bonds. Identification of these molecules is through their molecular formulas.

There is a hierarchy of formulas:

1. Empirical formula: Consider the benzene molecule which has 6 carbon and 6 hydrogen atoms. Therefore the ratio of carbon to hydrogen atoms is 6 to 6 which we can simplify to 1 to 1 (i.e., 1:1). The empirical formula expresses this most simple ratio, i.e. C1H1 (or CH). The empirical formula expresses the most simple ratio of atoms in the molecule. Examples:  methane: CH4, ethane CH3, water H2O, benzene CH, acetic acid COH2


Video Explanation:  Difference between empirical & molecular formula, How to calculate both:
Picture
2.  Molecular formulas: go one step beyond the empirical formula in that they express not only the correct ratio but the correct number of atoms in the molecule. In the case of benzene the molecular formula would be C6H6. other Examples:  methane CH4, benzene C6H6, ethane C2H6, acetic acid C2O2H4, water H2O ( Notice that sometimes the empirical and molecular formulas are the same. This will happen when the molecular formula also expresses the most simple ratio of atoms.)

Picture
3.  Structural formula: The structural formula not only has the correct number of atoms but includes the bonding structure of the molecule (i.e., which atoms are bonded together).

Picture
4. 3D Structural formula: Molecules are three dimensional (3D) objects. The 3D structural formula is an attempt to convey the 3D geometry of the molecule. dashed bonds depict atoms going in back of the plane. Note: The triangular bonds depict atoms coming out of the plane and the dashed bonds depict atoms going in back of the plane. Go Here if you would like to learn more about 3D structures


Picture

keentween

  • Ask
  • FAQ
  • Summer 2020 Tutoring
    • Pre-Algebra Sessions >
      • :: Basic Division
      • :: Complex Division
      • :: Estimation Division
      • :: Division Practice Problems
    • Algebra II >
      • :: Cubic Equations
      • :: Complex Numbers
    • Chemistry >
      • Molarity Basics
    • C++ Sessions >
      • :: Introduction
      • :: Style v Syntax
      • :: Variables & Data Types
      • :: Intialize/Declare Variables
      • :: Types of Operators
      • :: Strings and Input - Output
      • :: How to Construct Arrays
  • AP Bio
    • :: Sketch Notes >
      • :: Part 1
      • :: Part 2
    • :: Chi-Squared Tests
    • :: Cancer
    • :: Hox Genes
    • :: Hardy-Weinberg Principle
    • :: Rule of Multiplication + Addition for Punnett Squares
    • :: CRISPR
    • :: Amino Acid
    • :: Peptide
    • :: Why study Peptides
    • :: Aquaporins
    • :: Gram Stains
    • :: Graph on Excel for Bio Lab
  • AP Chem
    • Organic Chemistry
    • I. Properties of Matter >
      • Neutralization
    • II. Periodic table >
      • Org of Periodic Table
      • :: Groups
    • III. Chemical bonding >
      • :: Mass to Mass conversion
      • :: Naming Acids
      • :: Cross Drop Charge
      • :: Predicting Products
      • :: Balance Equation Question
      • :: Learn to Balance Equation
      • :: VSEPR Simulation
    • IV. Molar Mass >
      • ::LR ER and excess reatant
      • :: Molecular/Formula Mass
      • :: Empirical Formula & Molar Mass
      • :: Percentages & Empirical Formula
      • :: Empirical formula
    • IV. Solutions and Solubility >
      • :: Types of Solutions with Solubility Curves
      • :: Solubility Curve
    • V. Easy Tricks and Tips >
      • :: Tip to Molecular Shapes
      • Memorizing Bond Angles and Polarity
      • :: Chemistry Formulas
      • :: Trick Polyatomic ions
    • VI. General AP Concepts >
      • :: Potential Energy Diagrams
      • :: Haber-Bosch
      • :: Le Chatelier
      • :: Pressure & Moles
      • ::Rydberg's Constant vs Unit of Energy
      • :: Equilibrium and RICE Tables
      • :: Kinetics
      • Galvanic Cells
    • :: Flash cards
    • :: VSEPR
  • AP Stats
    • Chi-Squared Tests
    • Applications of Statistics
    • Standardized Scores
    • Distributions Transformations
  • AP Calc
    • DI Method - Tabular Integration
    • Polar Curves: Tangent Line and Slope
    • Riemann Sums: Left and Right Approximations
    • :: Conic Sections Flash cards
    • :: Parent Functions Flash cards
    • Worked Out Problems >
      • :: Worked Out Problems I
      • :: Worked Out Problems II
      • :: Worked Out Problems III
      • :: Worked Out Problems IV
      • :: Worked Out Problems V
      • :: Worked Out Problems VI
      • :: Worked Out Problems VII
      • :: Worked Out Problems VIII
      • :: Worked Out Problems IX
      • :: Worked Out Problems X
      • :: Worked Out Problems XI
      • :: Worked Out Problems XII
      • :: Worked Out Problems XIII
    • Applying Trig Identities
    • L'Hopital's Rule
    • Differences Between Conic Sections
    • Graphing Conic Sections
    • :: Pre-Calc - Trig Identities
    • Tangent & Normal Lines
    • Indefinite integrals: U Sub
    • Calculus Derivatives >
      • Product Rule
      • Quotient Rule
      • Chain Rule
  • AP CS A
    • Studying for AP CSA 2020
    • :: Control Structures
    • :: What is Networking
    • :: Recursion
    • :: While Do While Loops in Java
    • :: Interface in Java
    • :: ArrayLists
    • :: Java Naming Conventions
    • :: Logic Circuits
    • :: Getters and Setters
    • :: Binary & Hexadecimal
  • AP Español
    • AP Español Salsa
  • Arduino
    • Quick Look
    • Project #1: Blinking LED
    • Project #2: Button LED
    • Project #3: Flowing LED
    • Project #4: LCD Display
    • Project #5: Serial Monitor
  • App
    • AP Go Pow How?
    • AP Go Pow APP Page
  • Musings
    • :: Backward induction
    • :: what is ISS
    • :: Rotational Matrices
    • :: Primary v Secondary Pollutants
    • :: Black Hole
    • :: Covid-19 Hackathon
    • :: Evolution of Immunizations
    • :: Predictions of Diseases
    • :: Book List
    • :: Patterncount
    • :: Binary Classification
    • :: Cybersecurity
    • :: Self Similarity
    • :: Trig Identities
    • :: UIL Number S
    • :: Box Offensive Play
    • :: Why Card Trick Works
    • :: Easy Multiplication
  • AP CREDIT
  • About