Aha! Chemistry with Prof Bob
  • HOME
  • NAVIGATION
    • Table of contents
    • Index
    • TALK WITH PROF BOB?
  • LEARNING MODULES
    • Chapter 02 Stuff, matter: What is it? >
      • 0200 Stuff, matter: A theory of atoms
      • 0201 Atoms: The building blocks of all stuff
      • 0202 People classifying stuffs. Why?
    • Chapter 05 Chemical reactions, chemical equations >
      • 0500 Chemical reactions vs. chemical equations. Overview
      • 0501 Chemical amount and its unit of measurement, mole
      • 0502 The Avogadro constant: How many is that?
      • 0503 The Avogadro constant: Why is it that number?
      • 0504 Chemical formulas: What can they tell us??
      • 0505 Chemical equations: What can they tell us?
      • 0506 Limiting reactants: How much reaction can happen?
      • 0507 Balanced chemical equations: What are they?
      • 0508 Chemical reactions as competitions
    • Chapter 09 Aqueous solutions >
      • 0901 What is a solution? And what is not?
      • 0902 Miscibility of liquids in each other
      • 0903 Like dissolves like? Shades of grey
      • 0905 Dissolution of ionic salts in water: A competition
      • 0906 Can we predict solubilities of salts?
      • 0907 Solution concentration
      • 0908 Chemical species, speciation in aqueous solution
      • 0909 Solutes: Electrolytes or non-electrolytes?
      • 0910 Electrolytes - strong or weak?
      • 0911 Concentrated, dilute, strong, weak
      • 0912 Species concentration vs. solution concentration
      • 0913 Weak electrolytes: Getting quantitative
    • Chapter 11: Dynamic chemical equilibrium >
      • 1100 Dynamic chemical equilibrium: Overview
      • 1101 Visualising dynamic chemical equilibrium
      • 1102 The jargon of chemical equilibrium
      • 1103 Equilibrium constants: The law of equilibrium
      • 1104 The law of equilibrium: an analogy
    • Chapter 22 Spectroscopy >
      • 2200 Spectroscopy: Overview and preview
      • 2201 Quantisation of forms of energy
      • 2202 Light: Wave-particle "duality"
      • 2203 Ultraviolet-visible spectroscopy
      • 2204 Beer’s law: How much light is transmitted?
    • Chapter 27 The greenhouse effect, climate change >
      • 2700 The greenhouse effect: overview
      • 2701 Is Earth in energy balance?
      • 2702 CO2 in the atmosphere before 1800
      • 2703 So little CO2! Pffft?
      • 2704 Does CO2 affect Earth's energy balance?
      • 2705 The "greenhouse effect"
      • 2706 Why does CO2 absorb radiation from Earth?
      • 2707 The "enhanced greenhouse effect"
      • 2708 Why doesn't CO2 absorb the radiation from the sun?
      • 2709 Why are N2 and O2 not greenhouse gases?
      • 2710 Doesn't water vapour absorb all the IR?
      • 2711 Carbon dioxide from our cars
      • 2712 The source of energy from combustion
      • 2713 Comparing fuels as energy sources
      • 2714 Methane: How does it compare as a GHG?
      • 2715 Different sorts of pollution of the atmosphere
      • 2716 "Acidification" of seawater
    • Chapter 27 Communicating chemistry >
      • 2700 Overview, preview
      • 2703 The jargon we use
  • TEACHERS' CORNER
    • T01 Communicating chemistry
    • T02 Beer's law
    • T03 Professional amnesia of the chemistry teaching professio
    • T04 Law of equilibrium
    • T05 Visusalizing dynamic chemical equilibrium
    • Information vs. knowledge
  • PERSONAL GALLERY
    • Family
    • Travel
    • Playful dolphins
    • The University of Western Australia
    • Kings Park
    • Perth
    • At work
    • 999 Thermodynamics



Module 0500:

Chapter Introduction - overview, preview


​

Chemical reactions vs. chemical equations

Especially when you are setting out on the path of learning chemistry, it is fundamentally important to distinguish chemical reactions (real phenomena) and chemical equations (a form of language used to talk about chemical reactions).

​
Picture

KEY IDEAS - Chemical reactions vs. chemical equations

Picture
Some stuff is happening, and some people are talking about the stuff that is happening.

Chemical reactions

 
​Chemical reactions
 are real phenomena - often able to be seen, or at least to see evidence that a reaction has occured.

They include the burning of natural gas, the main component of which is methane - as pictured in the banner on Chapter 05 HOME.

And the electron-transfer processes that occur in batteries when they are providing us with energy, or when they are being re-charged.

And the oxidation-reduction life process of respiration, as well as of decomposition of dead matter, once living.

And the precipitation of limestone in caves.

And the reaction of carbon dioxide from the atmosphere in the upper layers of the ocean, making the water more acidic that it would otherwise be.

And rusting of steel structures and ships .......
​
​
​
​

Chemical equations


​Chemical equations, on the other hand, are a form of communication about chemical reactions. 

We use chemical equations to communicate information about chemical reactions. Some of this information is in response to qualitative questions like "What are the reactants?" and "What are the products?"


And if we have the appropriate balanced equation, we can find answers to quantitative questions like "How much of this reacts with how much of that?" and "How much of this product will be formed?"

​
​


A synopsis of the chapter: Reactions and equations


​In working with equations, questions of "How much?" are answered in terms of chemical amount (unit of measurement, the mole) so this way of measuring quantities needs to be understood to interpret chemical equations. Prof Bob discusses this link between mass of  a substance and the number of atoms, molecules, or ions in Module 0501: Chemical amount, and its unit of measurement, mole.
​
The number of particles in 1 mol of any substance (called the Avogadro constant) is astonishingly large, and almost too big a number to comprehend. Prof Bob tackles this challenge in Module 0502: The Avogadro constant: How many particles is that?
​
And why is the Avogadro constant the particular number that it is? Is it a universal constant? Or a random choice? See Module 0503: The Avogadro constant: Why is it that number?
​
To interpret correctly the meaning of the chemical formula of a substance, we need to know about the structure of the substance at the sub-microscopic level. In particular, how we interpret the formula of a substance characterized as an ionic compound is different from how we interpret the formula of a compound categorized as a covalent molecular compound. Prof Bob discusses this difference in Module 0504: Chemical formulas: How do we interpret them?
​
Balanced chemical equations are very powerful descriptions of chemical reactions, but sometimes people attribute more meaning to them than the information that they carry. The information that they do carry is extraordinarily important, and is the basis of all quantitative calculations. See Module 0505: Balanced chemical equations: What can they tell us?

If we mix some substances that react with each other, how much of the products can be formed? What decides the maximum amount of product that can be formed from the added amounts of the reactants? Aussie works his way through this issue with Prof Bob in Module 0506: Limiting reactants: What limits how much reaction can happen?
​
​

​
Picture
A famous painting by artist Rene Magritte, with an important message. This is not a pipe. OK then, what is it? The answer begins with 'R'.
Picture
A chemical reaction happening
Picture
Information about the reaction, including an equation.
Picture

LEARNING CHEMISTRY FOR UNDERSTANDING


Seek knowledge and wisdom, and enjoyment will follow


​
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  • HOME
  • NAVIGATION
    • Table of contents
    • Index
    • TALK WITH PROF BOB?
  • LEARNING MODULES
    • Chapter 02 Stuff, matter: What is it? >
      • 0200 Stuff, matter: A theory of atoms
      • 0201 Atoms: The building blocks of all stuff
      • 0202 People classifying stuffs. Why?
    • Chapter 05 Chemical reactions, chemical equations >
      • 0500 Chemical reactions vs. chemical equations. Overview
      • 0501 Chemical amount and its unit of measurement, mole
      • 0502 The Avogadro constant: How many is that?
      • 0503 The Avogadro constant: Why is it that number?
      • 0504 Chemical formulas: What can they tell us??
      • 0505 Chemical equations: What can they tell us?
      • 0506 Limiting reactants: How much reaction can happen?
      • 0507 Balanced chemical equations: What are they?
      • 0508 Chemical reactions as competitions
    • Chapter 09 Aqueous solutions >
      • 0901 What is a solution? And what is not?
      • 0902 Miscibility of liquids in each other
      • 0903 Like dissolves like? Shades of grey
      • 0905 Dissolution of ionic salts in water: A competition
      • 0906 Can we predict solubilities of salts?
      • 0907 Solution concentration
      • 0908 Chemical species, speciation in aqueous solution
      • 0909 Solutes: Electrolytes or non-electrolytes?
      • 0910 Electrolytes - strong or weak?
      • 0911 Concentrated, dilute, strong, weak
      • 0912 Species concentration vs. solution concentration
      • 0913 Weak electrolytes: Getting quantitative
    • Chapter 11: Dynamic chemical equilibrium >
      • 1100 Dynamic chemical equilibrium: Overview
      • 1101 Visualising dynamic chemical equilibrium
      • 1102 The jargon of chemical equilibrium
      • 1103 Equilibrium constants: The law of equilibrium
      • 1104 The law of equilibrium: an analogy
    • Chapter 22 Spectroscopy >
      • 2200 Spectroscopy: Overview and preview
      • 2201 Quantisation of forms of energy
      • 2202 Light: Wave-particle "duality"
      • 2203 Ultraviolet-visible spectroscopy
      • 2204 Beer’s law: How much light is transmitted?
    • Chapter 27 The greenhouse effect, climate change >
      • 2700 The greenhouse effect: overview
      • 2701 Is Earth in energy balance?
      • 2702 CO2 in the atmosphere before 1800
      • 2703 So little CO2! Pffft?
      • 2704 Does CO2 affect Earth's energy balance?
      • 2705 The "greenhouse effect"
      • 2706 Why does CO2 absorb radiation from Earth?
      • 2707 The "enhanced greenhouse effect"
      • 2708 Why doesn't CO2 absorb the radiation from the sun?
      • 2709 Why are N2 and O2 not greenhouse gases?
      • 2710 Doesn't water vapour absorb all the IR?
      • 2711 Carbon dioxide from our cars
      • 2712 The source of energy from combustion
      • 2713 Comparing fuels as energy sources
      • 2714 Methane: How does it compare as a GHG?
      • 2715 Different sorts of pollution of the atmosphere
      • 2716 "Acidification" of seawater
    • Chapter 27 Communicating chemistry >
      • 2700 Overview, preview
      • 2703 The jargon we use
  • TEACHERS' CORNER
    • T01 Communicating chemistry
    • T02 Beer's law
    • T03 Professional amnesia of the chemistry teaching professio
    • T04 Law of equilibrium
    • T05 Visusalizing dynamic chemical equilibrium
    • Information vs. knowledge
  • PERSONAL GALLERY
    • Family
    • Travel
    • Playful dolphins
    • The University of Western Australia
    • Kings Park
    • Perth
    • At work
    • 999 Thermodynamics