4.2.4

Hess’ Law

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Hess' Law

Hess' Law provides a useful way of calculating enthalpy changes.

Hess' Law

Hess' Law

The enthalpy change of a reaction is independent of the pathway.
- This means that the enthalpy change of the reaction is the same for if the reaction is direct or indirect.

What does this mean?

What does this mean?

Hess' Law is useful for obtaining enthalpy changes that aren't directly observable.
These are often obscure reactions.
With the help of some easy reactions that involve some of these compounds, we can derive the enthalpy changes we're interested in.

The break down

The break down

This means that the following will all have the same enthalpy change:
- A → B → C → D → E
- A → C → E
- A → E
Overall, they all just convert A to E and so the overall enthalpy change will be identical for all of them.

Hess Cycles

We can use Hess' Law to derive Hess Cycles which will help us with calculations. We can create cycles using enthalpies of formation or combustion.

Hess cycles

Hess cycles

Above shows how we can convert the principle of Hess' Law into an actual equation.
We can set up an equation using the pathways:
- ΔH₁ + ΔH₂ = ΔH₃
We can then subtitute in the known values and rearrange to find the unknown values.

Using enthalpies of formation

Using enthalpies of formation

The first type of Hess cycle is those that use enthalpies of formation to calculate an overall reaction's enthalpy change.
- We set up a cycle, as shown, which includes two enthalpies of formation arrows to create the cycle.

Using enthalpies of formation

Using enthalpies of formation

To do this we must know all the enthalpies of formation for the reactants and the products.
- The enthalpy of formation for any element is zero.

Using enthalpies of combustion

Using enthalpies of combustion

We can use a similar method to set up a cycle using enthalpies of combustion.
- Below ΔH₂ and ΔH₃ represent enthalpies of combustion.
  - This can be spotted by the combustion products: CO₂ + H₂O

1

Structure - Models of the Particulate of Matter

1.1

Introduction to the Particulate Model of Matter

1.1.1States of Matter 1.1.2Kinetic Molecular Theory 1.1.3Simple Sphere 1.1.4Changing State 1.1.5Forces Between Particles 1.1.6Changes of State 1.1.7Predicting States 1.1.8Changing State HyperLearning 1.1.9Ionization Energy

1.2

The Nuclear Atom

1.2.1Fundamental Particles 1.2.2Isotopes & Mass Number 1.2.3Mass Spectrometry 1.2.4Mass Spectrometry 1.2.5Mass Spectroscopy - Analysis 1.2.6Extended Response - Mass Spectrometry 1.2.7Radioactivity

1.3

Electron Configuration

1.3.1Electron Shells, Sub-Shells & Orbitals 1.3.2Electron Configuration 1.3.3Absorption & Emission Spectra 1.3.4IB Multiple Choice - Atomic Structure 1.3.5Extended Response - The Atom & Electrons

1.4

Counting Particles by Mass: The Mole

1.4.1Relative Masses 1.4.2The Mole 1.4.3IB Multiple Choice - Moles

1.5

Ideal Gases

1.5.1Ideal Gas Equation 1.5.2Gas Laws 1.5.3IB Multiple Choice - Gases & Kinetics

1.6

Elements, Compounds & Mixtures

1.6.1Fundamental Particles 1.6.2Pure Substances 1.6.3Purity & The Law of Definite Proportion 1.6.4Mixtures 1.6.5Separating Mixtures 1.6.6IB Multiple Choice - Pure Substances 1.6.7Extended Response - Moles & Pure Substances

1.7

States of Matter & Changes of State

1.7.1States of Matter 1.7.2Particle Diagrams 1.7.3IB Multiple Choice - Solids, Liquids, & Gases 1.7.4Balancing Equations & Ionic Equations 1.7.5Empirical & Molecular Formulas

1.8

Reacting Masses &. Volumes

1.8.1Balancing Equations & Ionic Equations 1.8.2Percentage Yield

1.9

Solutions

1.9.1Molarity 1.9.2Particulate Model of Solutions

2

Structure - Models of Bonding & Structure

2.1

The Ionic Model

2.1.1Ionic Bonding

2.2

The Covalent Model

2.2.1Covalent Bonds 2.2.2Complex Ions 2.2.3Factors Affecting Covalent Bond Strength 2.2.4Polarity

2.3

Covalent Structures

2.3.1Ionic Lewis Structures 2.3.2Covalent Lewis Structures 2.3.3VSEPR Theory 2.3.4Resonance Structures 2.3.5Allotropes of Carbon 2.3.6Formal Charge 2.3.7End of Topic Quiz - Bonding 2.3.8IB Multiple Choice - Bonding & Lewis Structures 2.3.9IB Multiple Choice - Resonance & Formal Charge

2.4

The Metallic Model

2.4.1Metallic Bonding

2.5

From Models to Materials

2.5.1Alloys 2.5.2Properties of Polymers 2.5.3Polymerisation Reactions 2.5.4Introduction to Alkenes 2.5.5Reactions of Alkenes 2.5.6End of Topic Quiz - Alkenes

2.6

Valence Electrons & Ionic Compounds

2.6.1Valence Electrons & Forming Ions 2.6.2Ionic Compounds 2.6.3End of Topic Quiz - Atoms & Ions 2.6.4IB Multiple Choice - Valence & Ions

2.7

Molecular Shape

2.7.1VSEPR 2.7.2Molecular Shapes 2.7.3Bond Hybridization 2.7.4IB Multiple Choice - VSEPR & Bond Hybridization 2.7.5Extended Response - Bonding & Molecular Shape

2.8

Intermolecular Forces

2.8.1Introduction to Intermolecular Forces 2.8.2London Dispersion Forces 2.8.3Dipole-Dipole Interactions 2.8.4Ion-Dipole Interactions 2.8.5Hydrogen Bonding 2.8.6Large Biomolecules 2.8.7IB Multiple Choice - Intermolecular Forces 2.8.8Extended Response - Hydrogen Bonding

3

Structure - Classification of Matter

3.1

The Periodic Table: Classification of Elements

3.1.1The Periodic Table 3.1.2Trends in the Periodic Table 3.1.3End of Topic Quiz - Periodicity & Trends 3.1.4Periodic Trends - Electronegativity & Affinity 3.1.5End of Topic Quiz - Periodic Trends 3.1.6IB Multiple Choice - Periodic Trends 3.1.7Extended Response - Periodic Table

3.2

Periodic Trends

3.2.1Atomic & Ionic Radii 3.2.2Ionisation & Electronegativity 3.2.3Metallic Behaviour & Oxides 3.2.4Period 3 Elements & Oxides 3.2.5Period 3 Oxides 3.2.6End of Topic Quiz - Period 3 3.2.7Periodic Trends: Blocks 3.2.8Redox Chemistry

3.3

Group 1 Alkali Metals

3.3.1Alkali Metals

3.4

Halogens

3.4.1Introduction to Halogens 3.4.2Reactions of Halogens 3.4.3Chlorine & Chlorate(I)3.4.4End of Topic Quiz - Group 7 3.4.5Exam-Style Question - Group 7 3.4.6End of Topic Quiz - Periodicity, Group 2 & 7

3.5

Noble gases, group 18

3.5.1Noble Gases

3.6

Functional Groups: Classification of Organic

3.6.1Nomenclature 3.6.2Trends in Physical Properties 3.6.3Saturated & Unsaturated Hydrocarbons 3.6.4Nomenclature contd.3.6.5Types of Formulas 3.6.6Isomerism 3.6.7Formulae 3.6.8Homologous Series 3.6.9Structural Isomers

3.7

Functional Group Chemistry

3.7.1Degrees of Substitution 3.7.2Arenes

3.8

Alkanes

3.8.1Alkanes 3.8.2Fractional Distillation 3.8.3Cracking 3.8.4Combustion 3.8.5Chlorination 3.8.6End of Topic Quiz - Alkanes

3.9

Alcohols

3.9.1Production of Alcohols 3.9.2Oxidation of Alcohols 3.9.3Oxidation of Alcohols - 2 3.9.4Elimination Reactions 3.9.5End of Topic Quiz - Alcohols 3.9.6Exam-Style Question - Alcohols

3.10

Halogenoalkanes

3.10.1Substitution Reactions 3.10.2Elimination Reactions 3.10.3Ozone Depletion 3.10.4End of Topic Quiz - Halogenoalkanes

4

Reactivity - What Drives Chemical Reaction?

4.1

Endothermic & Exothermic Reactions

4.1.1Endothermic & Exothermic Reactions 4.1.2Energy Diagrams 4.1.3Heat Transfer & Thermal Equilibrium 4.1.4IB Multiple Choice - Enthalpy & Energy

4.2

Enthalpy of Reaction, Formation, & Hess' Law

4.2.1Enthalpy of Reaction 4.2.2Bond Enthalpies 4.2.3Enthalpy of Formation 4.2.4Hess’ Law 4.2.5Thermodynamics & Kinetic Control 4.2.6End of Topic Quiz - Thermodynamics 4.2.7IB Multiple Choice - Enthalpy 4.2.8Extended Response - Enthalpy Change

4.3

Entropy

4.3.1Introduction to Entropy 4.3.2Absolute Entropy & Entropy Change 4.3.3Free Energy 4.3.4Thermodynamically Favorable Reactions 4.3.5IB Multiple Choice - Entropy & Free Energy 4.3.6Extended Response - Free Energy

5

Reactivity - How Much, How Fast & How Far?

5.1

Kinetics

5.1.1Collision Theory & Rates of Reaction 5.1.2Maxwell-Boltzmann Distribution 5.1.3Increasing Rates 5.1.4End of Topic Quiz - Kinetics

5.2

Rates of Reaction

5.2.1Rate Equations 5.2.2Rate Equations 2 5.2.3The Effect of a Catalyst

5.3

Stoichometry

5.3.1Stoichiometry

5.4

Le Châtelier’s Principle

5.4.1Introduction to Le Châtelier’s Principle 5.4.2Reaction Quotient & Le Châtelier’s Principle 5.4.3Temperature & Le Châtelier’s Principle 5.4.4IB Multiple Choice -Le Châtelier’s Principle 5.4.5Extended Response - Le Châtelier

5.5

Introduction to Equilibrium

5.5.1Equilibrium & Equilibrium Graphs 5.5.2Dynamic Equilibria 5.5.3Reversible Reactions & Directions

5.6

Equilibrium Constant

5.6.1Calculating the Equilibrium Constant 5.6.2Magnitude of the Equilibrium Constant 5.6.3Properties of the Equilibrium Constant 5.6.4Calculating Equilibrium Concentrations 5.6.5Representations of Equilibrium 5.6.6IB Multiple Choice - Equilibrium Constants 5.6.7Extended Response - Calculating Kc

5.7

Reaction Quotient & Equilibrium Constant

5.7.1Reaction Quotient 5.7.2Equilibrium Constants 5.7.3Partial Pressures 5.7.4Kp 5.7.5IB Multiple Choice - Reaction Quotient & Kp 5.7.6Extended Response - Kp & Bond Enthalpy

6

Reactivity - The Mechanisms of Chemical Change

6.1

Proton Transfer Reactions

6.1.1Brønsted-Lowry Theory

6.2

The pH Scale

6.2.1pH & pOH 6.2.2Ionic Product of Water 6.2.3Using Kw 6.2.4IB Multiple Choice - pH & Kw 6.2.5Extended Response - Kw

6.3

Strong & Weak Acids and Bases

6.3.1Strong Acids & Bases 6.3.2Weak Acids & Ka 6.3.3Weak Bases & Kb 6.3.4Weak Acids & Bases Calculation Walkthrough

6.4

Acid Deposition

6.4.1Acid Deposition

6.5

Types of Organic Reactions

6.5.1Electrophilic Substitution

6.6

Oxidation & Reduction

6.6.1Oxidation Number Method 6.6.2Winkler Method 6.6.3Redox Reactions 6.6.4Oxidation States & Equations 6.6.5End of Topic Quiz - Redox 6.6.6Extended Response - Redox Reactions

6.7

Electrochemical Cells

6.7.1Introduction to Electrochemical Cells 6.7.2Galvanic Cells 6.7.3Cell Notation 6.7.4Electrolytic Cells 6.7.5Extended Response - Voltaic Cells & Redox

6.8

Titration

6.8.1Redox Titrations 6.8.2Titration Calculations 6.8.3Atom Economy

6.9

Acid-Base Titrations

6.9.1Titration Calculation Weak Acid & Strong Base 6.9.2Titration Experimental Detail 6.9.3Extended Response - Titration 6.9.4Titration Calculations 6.9.5Titration Curves 6.9.6Titration Calculation Strong Acid & Weak Base 6.9.7IB Multiple Choice - Titrations 6.9.8Polyprotic Acids 6.9.9Titration Calculations Strong Acid & Strong Base 6.9.10Titrations Curves 2

7

Measurement, Data Processing & Analysis

7.1

Uncertainties & Errors in Measurements & Results

7.1.1Qualitative & Quantitative data

7.2

Graphical Techniques

7.2.1Drawing & Interpreting Graphs 7.2.2Linear Interpolation

7.3

Spectroscopic Identification of Organic Compounds

7.3.1Understanding NMR 7.3.2Carbon-13 NMR 7.3.3Hydrogen-1 NMR 7.3.4Hydrogen-1 NMR 2 7.3.5End of Topic Quiz - NMR

7.4

Infrared Spectroscpy

7.4.1Infrared Spectroscopy

Jump to other topics

1

Structure - Models of the Particulate of Matter

1.1

Introduction to the Particulate Model of Matter

1.1.1States of Matter 1.1.2Kinetic Molecular Theory 1.1.3Simple Sphere 1.1.4Changing State 1.1.5Forces Between Particles 1.1.6Changes of State 1.1.7Predicting States 1.1.8Changing State HyperLearning 1.1.9Ionization Energy

1.2

The Nuclear Atom

1.2.1Fundamental Particles 1.2.2Isotopes & Mass Number 1.2.3Mass Spectrometry 1.2.4Mass Spectrometry 1.2.5Mass Spectroscopy - Analysis 1.2.6Extended Response - Mass Spectrometry 1.2.7Radioactivity

1.3

Electron Configuration

1.3.1Electron Shells, Sub-Shells & Orbitals 1.3.2Electron Configuration 1.3.3Absorption & Emission Spectra 1.3.4IB Multiple Choice - Atomic Structure 1.3.5Extended Response - The Atom & Electrons

1.4

Counting Particles by Mass: The Mole

1.4.1Relative Masses 1.4.2The Mole 1.4.3IB Multiple Choice - Moles

1.5

Ideal Gases

1.5.1Ideal Gas Equation 1.5.2Gas Laws 1.5.3IB Multiple Choice - Gases & Kinetics

1.6

Elements, Compounds & Mixtures

1.6.1Fundamental Particles 1.6.2Pure Substances 1.6.3Purity & The Law of Definite Proportion 1.6.4Mixtures 1.6.5Separating Mixtures 1.6.6IB Multiple Choice - Pure Substances 1.6.7Extended Response - Moles & Pure Substances

1.7

States of Matter & Changes of State

1.7.1States of Matter 1.7.2Particle Diagrams 1.7.3IB Multiple Choice - Solids, Liquids, & Gases 1.7.4Balancing Equations & Ionic Equations 1.7.5Empirical & Molecular Formulas

1.8

Reacting Masses &. Volumes

1.8.1Balancing Equations & Ionic Equations 1.8.2Percentage Yield

1.9

Solutions

1.9.1Molarity 1.9.2Particulate Model of Solutions

2

Structure - Models of Bonding & Structure

2.1

The Ionic Model

2.1.1Ionic Bonding

2.2

The Covalent Model

2.2.1Covalent Bonds 2.2.2Complex Ions 2.2.3Factors Affecting Covalent Bond Strength 2.2.4Polarity

2.3

Covalent Structures

2.3.1Ionic Lewis Structures 2.3.2Covalent Lewis Structures 2.3.3VSEPR Theory 2.3.4Resonance Structures 2.3.5Allotropes of Carbon 2.3.6Formal Charge 2.3.7End of Topic Quiz - Bonding 2.3.8IB Multiple Choice - Bonding & Lewis Structures 2.3.9IB Multiple Choice - Resonance & Formal Charge

2.4

The Metallic Model

2.4.1Metallic Bonding

2.5

From Models to Materials

2.5.1Alloys 2.5.2Properties of Polymers 2.5.3Polymerisation Reactions 2.5.4Introduction to Alkenes 2.5.5Reactions of Alkenes 2.5.6End of Topic Quiz - Alkenes

2.6

Valence Electrons & Ionic Compounds

2.6.1Valence Electrons & Forming Ions 2.6.2Ionic Compounds 2.6.3End of Topic Quiz - Atoms & Ions 2.6.4IB Multiple Choice - Valence & Ions

2.7

Molecular Shape

2.7.1VSEPR 2.7.2Molecular Shapes 2.7.3Bond Hybridization 2.7.4IB Multiple Choice - VSEPR & Bond Hybridization 2.7.5Extended Response - Bonding & Molecular Shape

2.8

Intermolecular Forces

2.8.1Introduction to Intermolecular Forces 2.8.2London Dispersion Forces 2.8.3Dipole-Dipole Interactions 2.8.4Ion-Dipole Interactions 2.8.5Hydrogen Bonding 2.8.6Large Biomolecules 2.8.7IB Multiple Choice - Intermolecular Forces 2.8.8Extended Response - Hydrogen Bonding

3

Structure - Classification of Matter

3.1

The Periodic Table: Classification of Elements

3.1.1The Periodic Table 3.1.2Trends in the Periodic Table 3.1.3End of Topic Quiz - Periodicity & Trends 3.1.4Periodic Trends - Electronegativity & Affinity 3.1.5End of Topic Quiz - Periodic Trends 3.1.6IB Multiple Choice - Periodic Trends 3.1.7Extended Response - Periodic Table

3.2

Periodic Trends

3.2.1Atomic & Ionic Radii 3.2.2Ionisation & Electronegativity 3.2.3Metallic Behaviour & Oxides 3.2.4Period 3 Elements & Oxides 3.2.5Period 3 Oxides 3.2.6End of Topic Quiz - Period 3 3.2.7Periodic Trends: Blocks 3.2.8Redox Chemistry

3.3

Group 1 Alkali Metals

3.3.1Alkali Metals

3.4

Halogens

3.4.1Introduction to Halogens 3.4.2Reactions of Halogens 3.4.3Chlorine & Chlorate(I)3.4.4End of Topic Quiz - Group 7 3.4.5Exam-Style Question - Group 7 3.4.6End of Topic Quiz - Periodicity, Group 2 & 7

3.5

Noble gases, group 18

3.5.1Noble Gases

3.6

Functional Groups: Classification of Organic

3.6.1Nomenclature 3.6.2Trends in Physical Properties 3.6.3Saturated & Unsaturated Hydrocarbons 3.6.4Nomenclature contd.3.6.5Types of Formulas 3.6.6Isomerism 3.6.7Formulae 3.6.8Homologous Series 3.6.9Structural Isomers

3.7

Functional Group Chemistry

3.7.1Degrees of Substitution 3.7.2Arenes

3.8

Alkanes

3.8.1Alkanes 3.8.2Fractional Distillation 3.8.3Cracking 3.8.4Combustion 3.8.5Chlorination 3.8.6End of Topic Quiz - Alkanes

3.9

Alcohols

3.9.1Production of Alcohols 3.9.2Oxidation of Alcohols 3.9.3Oxidation of Alcohols - 2 3.9.4Elimination Reactions 3.9.5End of Topic Quiz - Alcohols 3.9.6Exam-Style Question - Alcohols

3.10

Halogenoalkanes

3.10.1Substitution Reactions 3.10.2Elimination Reactions 3.10.3Ozone Depletion 3.10.4End of Topic Quiz - Halogenoalkanes

4

Reactivity - What Drives Chemical Reaction?

4.1

Endothermic & Exothermic Reactions

4.1.1Endothermic & Exothermic Reactions 4.1.2Energy Diagrams 4.1.3Heat Transfer & Thermal Equilibrium 4.1.4IB Multiple Choice - Enthalpy & Energy

4.2

Enthalpy of Reaction, Formation, & Hess' Law

4.2.1Enthalpy of Reaction 4.2.2Bond Enthalpies 4.2.3Enthalpy of Formation 4.2.4Hess’ Law 4.2.5Thermodynamics & Kinetic Control 4.2.6End of Topic Quiz - Thermodynamics 4.2.7IB Multiple Choice - Enthalpy 4.2.8Extended Response - Enthalpy Change

4.3

Entropy

4.3.1Introduction to Entropy 4.3.2Absolute Entropy & Entropy Change 4.3.3Free Energy 4.3.4Thermodynamically Favorable Reactions 4.3.5IB Multiple Choice - Entropy & Free Energy 4.3.6Extended Response - Free Energy

5

Reactivity - How Much, How Fast & How Far?

5.1

Kinetics

5.1.1Collision Theory & Rates of Reaction 5.1.2Maxwell-Boltzmann Distribution 5.1.3Increasing Rates 5.1.4End of Topic Quiz - Kinetics

5.2

Rates of Reaction

5.2.1Rate Equations 5.2.2Rate Equations 2 5.2.3The Effect of a Catalyst

5.3

Stoichometry

5.3.1Stoichiometry

5.4

Le Châtelier’s Principle

5.4.1Introduction to Le Châtelier’s Principle 5.4.2Reaction Quotient & Le Châtelier’s Principle 5.4.3Temperature & Le Châtelier’s Principle 5.4.4IB Multiple Choice -Le Châtelier’s Principle 5.4.5Extended Response - Le Châtelier

5.5

Introduction to Equilibrium

5.5.1Equilibrium & Equilibrium Graphs 5.5.2Dynamic Equilibria 5.5.3Reversible Reactions & Directions

5.6

Equilibrium Constant

5.6.1Calculating the Equilibrium Constant 5.6.2Magnitude of the Equilibrium Constant 5.6.3Properties of the Equilibrium Constant 5.6.4Calculating Equilibrium Concentrations 5.6.5Representations of Equilibrium 5.6.6IB Multiple Choice - Equilibrium Constants 5.6.7Extended Response - Calculating Kc

5.7

Reaction Quotient & Equilibrium Constant

5.7.1Reaction Quotient 5.7.2Equilibrium Constants 5.7.3Partial Pressures 5.7.4Kp 5.7.5IB Multiple Choice - Reaction Quotient & Kp 5.7.6Extended Response - Kp & Bond Enthalpy

6

Reactivity - The Mechanisms of Chemical Change

6.1

Proton Transfer Reactions

6.1.1Brønsted-Lowry Theory

6.2

The pH Scale

6.2.1pH & pOH 6.2.2Ionic Product of Water 6.2.3Using Kw 6.2.4IB Multiple Choice - pH & Kw 6.2.5Extended Response - Kw

6.3

Strong & Weak Acids and Bases

6.3.1Strong Acids & Bases 6.3.2Weak Acids & Ka 6.3.3Weak Bases & Kb 6.3.4Weak Acids & Bases Calculation Walkthrough

6.4

Acid Deposition

6.4.1Acid Deposition

6.5

Types of Organic Reactions

6.5.1Electrophilic Substitution

6.6

Oxidation & Reduction

6.6.1Oxidation Number Method 6.6.2Winkler Method 6.6.3Redox Reactions 6.6.4Oxidation States & Equations 6.6.5End of Topic Quiz - Redox 6.6.6Extended Response - Redox Reactions

6.7

Electrochemical Cells

6.7.1Introduction to Electrochemical Cells 6.7.2Galvanic Cells 6.7.3Cell Notation 6.7.4Electrolytic Cells 6.7.5Extended Response - Voltaic Cells & Redox

6.8

Titration

6.8.1Redox Titrations 6.8.2Titration Calculations 6.8.3Atom Economy

6.9

Acid-Base Titrations

6.9.1Titration Calculation Weak Acid & Strong Base 6.9.2Titration Experimental Detail 6.9.3Extended Response - Titration 6.9.4Titration Calculations 6.9.5Titration Curves 6.9.6Titration Calculation Strong Acid & Weak Base 6.9.7IB Multiple Choice - Titrations 6.9.8Polyprotic Acids 6.9.9Titration Calculations Strong Acid & Strong Base 6.9.10Titrations Curves 2

7

Measurement, Data Processing & Analysis

7.1

Uncertainties & Errors in Measurements & Results

7.1.1Qualitative & Quantitative data

7.2

Graphical Techniques

7.2.1Drawing & Interpreting Graphs 7.2.2Linear Interpolation

7.3

Spectroscopic Identification of Organic Compounds

7.3.1Understanding NMR 7.3.2Carbon-13 NMR 7.3.3Hydrogen-1 NMR 7.3.4Hydrogen-1 NMR 2 7.3.5End of Topic Quiz - NMR

7.4

Infrared Spectroscpy

7.4.1Infrared Spectroscopy

Practice questions on Hess’ Law

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1
If the products were CO + H<sub>2</sub>O, what would the reactants be for the enthalpy of formation equation?Multiple choice
2
Which of the following does NOT have an enthalpy of formation of zero?Multiple choice

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Enthalpy of Formation

Thermodynamics & Kinetic Control